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/library_test.go

@@ -23,7 +23,6 @@ import (
 
 // Test that variants are being generated correctly, and that crate-types are correct.
 func TestLibraryVariants(t *testing.T) {
-	t.Parallel()
 
 	ctx := testRust(t, `
 		rust_library_host {
@@ -72,7 +71,6 @@ func TestLibraryVariants(t *testing.T) {
 
 // Test that dylibs are not statically linking the standard library.
 func TestDylibPreferDynamic(t *testing.T) {
-	t.Parallel()
 	ctx := testRust(t, `
 		rust_library_host_dylib {
 			name: "libfoo",
@@ -88,7 +86,6 @@ func TestDylibPreferDynamic(t *testing.T) {
 }
 
 func TestValidateLibraryStem(t *testing.T) {
-	t.Parallel()
 	testRustError(t, "crate_name must be defined.", `
 			rust_library_host {
 				name: "libfoo",
@@ -126,7 +123,6 @@ func TestValidateLibraryStem(t *testing.T) {
 }
 
 func TestSharedLibrary(t *testing.T) {
-	t.Parallel()
 	ctx := testRust(t, `
 		rust_ffi_shared {
 			name: "libfoo",
@@ -149,7 +145,6 @@ func TestSharedLibrary(t *testing.T) {
 }
 
 func TestStaticLibraryLinkage(t *testing.T) {
-	t.Parallel()
 	ctx := testRust(t, `
 		rust_ffi_static {
 			name: "libfoo",
@@ -167,7 +162,6 @@ func TestStaticLibraryLinkage(t *testing.T) {
 
 // Test that variants pull in the right type of rustlib autodep
 func TestAutoDeps(t *testing.T) {
-	t.Parallel()
 
 	ctx := testRust(t, `
                 rust_library_host {
@@ -215,7 +209,6 @@ func TestAutoDeps(t *testing.T) {
 
 // Test that stripped versions are correctly generated and used.
 func TestStrippedLibrary(t *testing.T) {
-	t.Parallel()
 	ctx := testRust(t, `
 		rust_library_dylib {
 			name: "libfoo",
@@ -247,7 +240,6 @@ func TestStrippedLibrary(t *testing.T) {
 }
 
 func TestLibstdLinkage(t *testing.T) {
-	t.Parallel()
 	ctx := testRust(t, `
 		rust_library {
 			name: "libfoo",