Add t.Parallel() to java tests

Speeds up go test ./java from 32 seconds to 9 seconds.

Test: go test ./java
Change-Id: I4c6640e787c0744c6dfda03b7382839b452e24cf
diff --git a/java/android_manifest_test.go b/java/android_manifest_test.go
index 7c91884..edb22fc 100644
--- a/java/android_manifest_test.go
+++ b/java/android_manifest_test.go
@@ -21,6 +21,7 @@
 )
 
 func TestManifestMerger(t *testing.T) {
+	t.Parallel()
 	bp := `
 		android_app {
 			name: "app",
@@ -100,6 +101,7 @@
 }
 
 func TestManifestValuesApplicationIdSetsPackageName(t *testing.T) {
+	t.Parallel()
 	bp := `
 		android_test {
 			name: "test",