Make lots of tests run in parallel

Putting t.Parallel() in each test makes them run in parallel.
Additional t.Parallel() could be added to each subtest, although
that requires making a local copy of the loop variable for
table driven tests.

Test: m checkbuild
Change-Id: I5d9869ead441093f4d7c5757f2447385333a95a4
diff --git a/java/sdk_test.go b/java/sdk_test.go
index 776069d..374da11 100644
--- a/java/sdk_test.go
+++ b/java/sdk_test.go
@@ -27,6 +27,7 @@
 )
 
 func TestClasspath(t *testing.T) {
+	t.Parallel()
 	var classpathTestcases = []struct {
 		name       string
 		unbundled  bool