fix: fix error message if emulator host is set

Author: olavloite

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionOptions.java

@@ -775,7 +775,7 @@ private void checkLocalConnection() {
         }
       } catch (UnavailableException e) {
         String msg;
-        if (emulatorHost == null) {
+        if (getHost() != null) {
           msg =
               String.format(
                   "The connection string '%s' contains host '%s', but no running"

google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionOptionsTest.java

@@ -492,8 +492,6 @@ public void testLocalConnectionError() {
           .contains(
               String.format(
                   "The connection string '%s' contains host 'localhost:1', but no running", uri));
-    } finally {
-      SpannerPool.closeSpannerPool();
     }
   }