Make lots of tests run in parallel

Putting t.Parallel() in each test makes them run in parallel.
Additional t.Parallel() could be added to each subtest, although
that requires making a local copy of the loop variable for
table driven tests.

Test: m checkbuild
Change-Id: I5d9869ead441093f4d7c5757f2447385333a95a4

dexpreopt/dexpreopt_test.go

@@ -61,6 +61,7 @@ func testModuleConfig(ctx android.PathContext, name, partition string) *ModuleCo
 }
 
 func TestDexPreopt(t *testing.T) {
+	t.Parallel()
 	config := android.TestConfig("out", nil, "", nil)
 	ctx := android.PathContextForTesting(config)
 	globalSoong := GlobalSoongConfigForTests(config)
@@ -83,6 +84,7 @@ func TestDexPreopt(t *testing.T) {
 }
 
 func TestDexPreoptSystemOther(t *testing.T) {
+	t.Parallel()
 	config := android.TestConfig("out", nil, "", nil)
 	ctx := android.PathContextForTesting(config)
 	globalSoong := GlobalSoongConfigForTests(config)
@@ -143,6 +145,7 @@ func TestDexPreoptSystemOther(t *testing.T) {
 }
 
 func TestDexPreoptProfile(t *testing.T) {
+	t.Parallel()
 	config := android.TestConfig("out", nil, "", nil)
 	ctx := android.PathContextForTesting(config)
 	globalSoong := GlobalSoongConfigForTests(config)