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

cmd/path_interposer/main_test.go

@@ -61,7 +61,6 @@ func setup(t *testing.T) string {
 }
 
 func TestInterposer(t *testing.T) {
-	t.Parallel()
 	interposer := setup(t)
 
 	logConfig := func(name string) paths.PathConfig {
@@ -181,7 +180,6 @@ func TestInterposer(t *testing.T) {
 }
 
 func TestMissingPath(t *testing.T) {
-	t.Parallel()
 	interposer := setup(t)
 	err := os.Remove(interposer + "_origpath")
 	if err != nil {