[ggj][bazel] feat: add java_gapic_test Bazel rule (#322)

* feat: add protobuf comment parser util

* fix: add basic proto build rules

* feat: add header comments to ServiceClient

* fix: build protoc at test time

* fix!: wrap protobuf location and process comments

* feat: add comment parsing to methods and fields

* fix: test

* feat: add protobuf comments to ServiceClient

* fix: solidify codegen method order with TypeNode/MethodArg and Comparable

* fix: clean up tests

* fix: ServiceClient member variables and method calls

* fix: ServiceStubSettings builder type

* fix: ServiceSettings Builder construction

* fix: ServiceStub callable types

* feat: java_gapic_library rule impl

* fix: remove debugging comments

* feat: add gradle assembly Bazel rules

* feat: add java_gapic_test Bazel rule

rules_java_gapic/java_gapic.bzl

@@ -156,3 +156,17 @@ def java_gapic_library(
         deps = [":%s" % name] + actual_test_deps,
         **kwargs
     )
+
+def java_gapic_test(name, runtime_deps, test_classes, **kwargs):
+    for test_class in test_classes:
+        native.java_test(
+            name = test_class,
+            test_class = test_class,
+            runtime_deps = runtime_deps,
+            **kwargs
+        )
+    native.test_suite(
+        name = name,
+        tests = test_classes,
+        **kwargs
+    )