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

androidmk/parser/make_strings_test.go

@@ -89,7 +89,6 @@ var splitNTestCases = []struct {
 }
 
 func TestMakeStringSplitN(t *testing.T) {
-	t.Parallel()
 	for _, test := range splitNTestCases {
 		got := test.in.SplitN(test.sep, test.n)
 		gotString := dumpArray(got)
@@ -119,7 +118,6 @@ var valueTestCases = []struct {
 }
 
 func TestMakeStringValue(t *testing.T) {
-	t.Parallel()
 	for _, test := range valueTestCases {
 		got := test.in.Value(nil)
 		if got != test.expected {
@@ -163,7 +161,6 @@ var splitWordsTestCases = []struct {
 }
 
 func TestMakeStringWords(t *testing.T) {
-	t.Parallel()
 	for _, test := range splitWordsTestCases {
 		got := test.in.Words()
 		gotString := dumpArray(got)

androidmk/parser/parser_test.go

@@ -37,7 +37,6 @@ var parserTestCases = []struct {
 }
 
 func TestParse(t *testing.T) {
-	t.Parallel()
 	for _, test := range parserTestCases {
 		t.Run(test.name, func(t *testing.T) {
 			p := NewParser(test.name, bytes.NewBufferString(test.in))