Remove MockWebServer from JwtIssuerAuthenticationManagerResolverTests

[rwinch]

JwtIssuerAuthenticationManagerResolverTests uses MockWebServer which is flakey on GitHub Windows runners due to resource contention of MockWebServer. The end result is that we occassionally get read timeouts like:

Exception
java.lang.IllegalArgumentException: Unable to resolve the Configuration with the provided Issuer of "http://127.0.0.1:51003/"	
at org.springframework.security.oauth2.jwt.JwtDecoderProviderConfigurationUtils.getConfiguration(JwtDecoderProviderConfigurationUtils.java:176)	
at org.springframework.security.oauth2.jwt.JwtDecoderProviderConfigurationUtils.getConfigurationForIssuerLocation(JwtDecoderProviderConfigurationUtils.java:88)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder.lambda$withIssuerLocation$2(NimbusJwtDecoder.java:232)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder$JwkSetUriJwtDecoderBuilder.jwkSource(NimbusJwtDecoder.java:461)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder$JwkSetUriJwtDecoderBuilder.processor(NimbusJwtDecoder.java:470)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder$JwkSetUriJwtDecoderBuilder.build(NimbusJwtDecoder.java:486)	
at org.springframework.security.oauth2.jwt.JwtDecoders.fromIssuerLocation(JwtDecoders.java:92)	
at org.springframework.security.oauth2.server.resource.authentication.JwtIssuerAuthenticationManagerResolver$TrustedIssuerJwtAuthenticationManagerResolver.lambda$resolve$0(JwtIssuerAuthenticationManagerResolver.java:210)	
•••
at org.springframework.security.oauth2.server.resource.authentication.JwtIssuerAuthenticationManagerResolver$TrustedIssuerJwtAuthenticationManagerResolver.resolve(JwtIssuerAuthenticationManagerResolver.java:207)	
at org.springframework.security.oauth2.server.resource.authentication.JwtIssuerAuthenticationManagerResolverTests.resolveWhenUsingSameIssuerThenReturnsSameAuthenticationManager(JwtIssuerAuthenticationManagerResolverTests.java:181)	
•••
Caused by: org.springframework.web.client.ResourceAccessException: I/O error on GET request for "http://127.0.0.1:51003/.well-known/openid-configuration": Read timed out	
at org.springframework.web.client.RestTemplate.createResourceAccessException(RestTemplate.java:780)	
•••
at org.springframework.security.oauth2.jwt.JwtDecoderProviderConfigurationUtils.getConfiguration(JwtDecoderProviderConfigurationUtils.java:165)	
at org.springframework.security.oauth2.jwt.JwtDecoderProviderConfigurationUtils.getConfigurationForIssuerLocation(JwtDecoderProviderConfigurationUtils.java:88)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder.lambda$withIssuerLocation$2(NimbusJwtDecoder.java:232)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder$JwkSetUriJwtDecoderBuilder.jwkSource(NimbusJwtDecoder.java:461)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder$JwkSetUriJwtDecoderBuilder.processor(NimbusJwtDecoder.java:470)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder$JwkSetUriJwtDecoderBuilder.build(NimbusJwtDecoder.java:486)	
at org.springframework.security.oauth2.jwt.JwtDecoders.fromIssuerLocation(JwtDecoders.java:92)	
at org.springframework.security.oauth2.server.resource.authentication.JwtIssuerAuthenticationManagerResolver$TrustedIssuerJwtAuthenticationManagerResolver.lambda$resolve$0(JwtIssuerAuthenticationManagerResolver.java:210)	
•••
at org.springframework.security.oauth2.server.resource.authentication.JwtIssuerAuthenticationManagerResolver$TrustedIssuerJwtAuthenticationManagerResolver.resolve(JwtIssuerAuthenticationManagerResolver.java:207)	
at org.springframework.security.oauth2.server.resource.authentication.JwtIssuerAuthenticationManagerResolverTests.resolveWhenUsingSameIssuerThenReturnsSameAuthenticationManager(JwtIssuerAuthenticationManagerResolverTests.java:181)	
•••
Caused by: java.net.SocketTimeoutException: Read timed out	
at sun.nio.ch.NioSocketImpl.timedRead(NioSocketImpl.java:288)	
•••
at org.springframework.security.oauth2.jwt.JwtDecoderProviderConfigurationUtils.getConfiguration(JwtDecoderProviderConfigurationUtils.java:165)	
at org.springframework.security.oauth2.jwt.JwtDecoderProviderConfigurationUtils.getConfigurationForIssuerLocation(JwtDecoderProviderConfigurationUtils.java:88)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder.lambda$withIssuerLocation$2(NimbusJwtDecoder.java:232)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder$JwkSetUriJwtDecoderBuilder.jwkSource(NimbusJwtDecoder.java:461)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder$JwkSetUriJwtDecoderBuilder.processor(NimbusJwtDecoder.java:470)	
at org.springframework.security.oauth2.jwt.NimbusJwtDecoder$JwkSetUriJwtDecoderBuilder.build(NimbusJwtDecoder.java:486)	
at org.springframework.security.oauth2.jwt.JwtDecoders.fromIssuerLocation(JwtDecoders.java:92)	
at org.springframework.security.oauth2.server.resource.authentication.JwtIssuerAuthenticationManagerResolver$TrustedIssuerJwtAuthenticationManagerResolver.lambda$resolve$0(JwtIssuerAuthenticationManagerResolver.java:210)	
•••
at org.springframework.security.oauth2.server.resource.authentication.JwtIssuerAuthenticationManagerResolver$TrustedIssuerJwtAuthenticationManagerResolver.resolve(JwtIssuerAuthenticationManagerResolver.java:207)	
at org.springframework.security.oauth2.server.resource.authentication.JwtIssuerAuthenticationManagerResolverTests.resolveWhenUsingSameIssuerThenReturnsSameAuthenticationManager(JwtIssuerAuthenticationManagerResolverTests.java:181)	
•••

We should remove the MockWebServer in favor of mocking.