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/droiddoc_test.go b/java/droiddoc_test.go
index 9e1ebbe..2256f1e 100644
--- a/java/droiddoc_test.go
+++ b/java/droiddoc_test.go
@@ -23,6 +23,7 @@
 )
 
 func TestDroiddoc(t *testing.T) {
+	t.Parallel()
 	ctx, _ := testJavaWithFS(t, `
 		droiddoc_exported_dir {
 		    name: "droiddoc-templates-sdk",
@@ -97,6 +98,7 @@
 }
 
 func TestDroiddocArgsAndFlagsCausesError(t *testing.T) {
+	t.Parallel()
 	testJavaError(t, "flags is set. Cannot set args", `
 		droiddoc_exported_dir {
 		    name: "droiddoc-templates-sdk",