Set test sizes to "small" as appropriate

This eliminates warnings that these tests are sized too big, since the
default is "medium".

cpp/BUILD

@@ -16,4 +16,5 @@ cc_test(
     name = "cpp_test",
     srcs = ["hello_test.cc"],
     deps = [":cpp_lib"],
+    size = "small",
 )

infra/msvc_filter_showincludes/BUILD

@@ -23,4 +23,5 @@ go_test(
     srcs = ["msvc_filter_showincludes_test.go"],
     embed = [":msvc_filter_showincludes_lib"],
     deps = ["@com_github_google_go_cmp//cmp"],
+    size = "small",
 )

java/com/engflow/example/BUILD

@@ -9,4 +9,5 @@ java_test(
     name = "ExampleTest",
     srcs = ["ExampleTest.java"],
     deps = [":example"],
+    size = "small",
 )

python/BUILD

@@ -25,6 +25,7 @@ py_test(
         ":hello",
         "@io_abseil_py//absl/testing:absltest",
     ],
+    size = "small",
 )
 
 # This wrapper supports sharding, fast-failing and test filtering: try
@@ -36,12 +37,14 @@ pytest_test(
     shard_count = 2,
     tags = ["todo-pe1188-remote-incompatible"],
     deps = [":hello"],
+    size = "small",
 )
 
 py_test(
     name = "hello_unittest_test",
     srcs = ["hello_unittest_test.py"],
     deps = [":hello"],
+    size = "small",
 )
 
 # Utility to help re-generate requirements lock.

scala/com/engflow/example/BUILD

@@ -9,4 +9,5 @@ scala_test(
     name = "exampleScalaTest",
     srcs = ["ScalaExampleTest.scala"],
     deps = [":exampleScala"],
+    size = "small",
 )