Mark test helpers as helpers.

This enables identifying the correct location of test failures.

from godocs:
Helper marks the calling function as a test helper function.
When printing file and line information, that function will be skipped.
Helper may be called simultaneously from multiple goroutines.

Test: go test bp2build tests
Change-Id: I52430e541494c78f5222c11510a4d273fe205a06

bp2build/cc_library_conversion_test.go

@@ -41,6 +41,7 @@ toolchain_library {
 )
 
 func runCcLibraryTestCase(t *testing.T, tc bp2buildTestCase) {
+	t.Helper()
 	runBp2BuildTestCase(t, registerCcLibraryModuleTypes, tc)
 }
 
@@ -52,6 +53,7 @@ func registerCcLibraryModuleTypes(ctx android.RegistrationContext) {
 }
 
 func runBp2BuildTestCase(t *testing.T, registerModuleTypes func(ctx android.RegistrationContext), tc bp2buildTestCase) {
+	t.Helper()
 	dir := "."
 	filesystem := make(map[string][]byte)
 	toParse := []string{

bp2build/cc_library_headers_conversion_test.go

@@ -84,6 +84,7 @@ func registerCcLibraryHeadersModuleTypes(ctx android.RegistrationContext) {
 }
 
 func runCcLibraryHeadersTestCase(t *testing.T, tc bp2buildTestCase) {
+	t.Helper()
 	runBp2BuildTestCase(t, registerCcLibraryHeadersModuleTypes, tc)
 }
 

bp2build/cc_library_static_conversion_test.go

@@ -76,6 +76,7 @@ func registerCcLibraryStaticModuleTypes(ctx android.RegistrationContext) {
 }
 
 func runCcLibraryStaticTestCase(t *testing.T, tc bp2buildTestCase) {
+	t.Helper()
 	runBp2BuildTestCase(t, registerCcLibraryStaticModuleTypes, tc)
 }
 

bp2build/cc_object_conversion_test.go

@@ -27,6 +27,7 @@ func registerCcObjectModuleTypes(ctx android.RegistrationContext) {
 }
 
 func runCcObjectTestCase(t *testing.T, tc bp2buildTestCase) {
+	t.Helper()
 	runBp2BuildTestCase(t, registerCcObjectModuleTypes, tc)
 }
 

bp2build/python_binary_conversion_test.go

@@ -8,6 +8,7 @@ import (
 )
 
 func runPythonTestCase(t *testing.T, tc bp2buildTestCase) {
+	t.Helper()
 	runBp2BuildTestCase(t, func(ctx android.RegistrationContext) {}, tc)
 }
 

bp2build/sh_conversion_test.go

@@ -49,6 +49,7 @@ func TestShBinaryLoadStatement(t *testing.T) {
 }
 
 func runShBinaryTestCase(t *testing.T, tc bp2buildTestCase) {
+	t.Helper()
 	runBp2BuildTestCase(t, func(ctx android.RegistrationContext) {}, tc)
 }