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

android/soong_config_modules_test.go

@@ -38,6 +38,7 @@ func soongConfigTestModuleFactory() Module {
 func (t soongConfigTestModule) GenerateAndroidBuildActions(ModuleContext) {}
 
 func TestSoongConfigModule(t *testing.T) {
+	t.Parallel()
 	configBp := `
 		soong_config_module_type {
 			name: "acme_test_defaults",