Revert "Make lots of tests run in parallel"

This reverts commit 323dc60712.

Reason for revert: Possible cause of test instability
Bug: 170513220
Test: soong tests

Change-Id: Iee168e9fbb4210569e6cffcc23e60d111403abb8

android/package_test.go

@@ -56,7 +56,6 @@ var packageTests = []struct {
 }
 
 func TestPackage(t *testing.T) {
-	t.Parallel()
 	for _, test := range packageTests {
 		t.Run(test.name, func(t *testing.T) {
 			_, errs := testPackage(test.fs)