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

rust/compiler_test.go

@@ -23,7 +23,6 @@ import (
 
 // Test that feature flags are being correctly generated.
 func TestFeaturesToFlags(t *testing.T) {
-	t.Parallel()
 	ctx := testRust(t, `
 		rust_library_host_dylib {
 			name: "libfoo",
@@ -45,7 +44,6 @@ func TestFeaturesToFlags(t *testing.T) {
 
 // Test that we reject multiple source files.
 func TestEnforceSingleSourceFile(t *testing.T) {
-	t.Parallel()
 
 	singleSrcError := "srcs can only contain one path for a rust file and source providers prefixed by \":\""
 
@@ -80,7 +78,6 @@ func TestEnforceSingleSourceFile(t *testing.T) {
 }
 
 func TestInstallDir(t *testing.T) {
-	t.Parallel()
 	ctx := testRust(t, `
 		rust_library_dylib {
 			name: "libfoo",
@@ -111,7 +108,6 @@ func TestInstallDir(t *testing.T) {
 }
 
 func TestLints(t *testing.T) {
-	t.Parallel()
 
 	bp := `
 		// foo uses the default value of lints
@@ -184,7 +180,6 @@ func TestLints(t *testing.T) {
 
 // Test that devices are linking the stdlib dynamically
 func TestStdDeviceLinkage(t *testing.T) {
-	t.Parallel()
 	ctx := testRust(t, `
 		rust_binary {
 			name: "fizz",