chore: test moving junit-related native config to src/test

Author: diegomarquezp

google-cloud-spanner/src/main/resources/META-INF/native-image/native-image.properties

@@ -1,5 +1,2 @@
 Args = --initialize-at-build-time=com.google.cloud.spanner.IntegrationTestEnv,\
-  org.junit.experimental.categories.CategoryValidator,\
-  org.junit.validator.AnnotationValidator,\
-  java.lang.annotation.Annotation \
   --features=com.google.cloud.spanner.nativeimage.SpannerFeature

google-cloud-spanner/src/test/resources/META-INF/native-image/com.google.cloud/google-cloud-spanner/native-image.properties

@@ -1,3 +1,6 @@
 Args=--initialize-at-build-time=org.junit.runner.RunWith \
  --initialize-at-build-time=org.junit.experimental.categories.Category \
- --initialize-at-build-time=org.junit.runners.model.FrameworkField
+ --initialize-at-build-time=org.junit.runners.model.FrameworkField \
+ --initialize-at-build-time=org.junit.experimental.categories.CategoryValidator \
+ --initialize-at-build-time=org.junit.validator.AnnotationValidator \
+ --initialize-at-build-time=java.lang.annotation.Annotation