Make apex tests parallel

Mark all the apex tests and subtests with t.Parallel(), which will allow
the test runner to run them in parallel.  Reduces the time required to
run the apex tests from 70s to 9.7s.

Test: go test ./apex
Flag: EXEMPT test only
Change-Id: I08bd3cb4d8eec1f9520c1118b4525aa79e95288e
diff --git a/apex/classpath_element_test.go b/apex/classpath_element_test.go
index 9e1ac94..f8e8899 100644
--- a/apex/classpath_element_test.go
+++ b/apex/classpath_element_test.go
@@ -40,6 +40,7 @@
 var _ java.ClasspathElementContext = (*testClasspathElementContext)(nil)
 
 func TestCreateClasspathElements(t *testing.T) {
+	t.Parallel()
 	preparer := android.GroupFixturePreparers(
 		prepareForTestWithPlatformBootclasspath,
 		prepareForTestWithArtApex,
@@ -240,6 +241,7 @@
 
 	// Verify that CreateClasspathElements works when given valid input.
 	t.Run("art:baz, art:quuz, my:bar, foo", func(t *testing.T) {
+		t.Parallel()
 		ctx := newCtx()
 		elements := java.CreateClasspathElements(ctx, []android.Module{artBaz, artQuuz, myBar, platformFoo}, []android.Module{artFragment, myFragment})
 		expectedElements := java.ClasspathElements{
@@ -252,6 +254,7 @@
 
 	// Verify that CreateClasspathElements detects when an apex has multiple fragments.
 	t.Run("multiple fragments for same apex", func(t *testing.T) {
+		t.Parallel()
 		ctx := newCtx()
 		elements := java.CreateClasspathElements(ctx, []android.Module{}, []android.Module{artFragment, artFragment})
 		android.FailIfNoMatchingErrors(t, "apex com.android.art has multiple fragments, art-bootclasspath-fragment{.*} and art-bootclasspath-fragment{.*}", ctx.errs)
@@ -261,6 +264,7 @@
 
 	// Verify that CreateClasspathElements detects when a library is in multiple fragments.
 	t.Run("library from multiple fragments", func(t *testing.T) {
+		t.Parallel()
 		ctx := newCtx()
 		elements := java.CreateClasspathElements(ctx, []android.Module{other}, []android.Module{artFragment, myFragment})
 		android.FailIfNoMatchingErrors(t, "library othersdklibrary{.*} is in two separate fragments, art-bootclasspath-fragment{.*} and mybootclasspath-fragment{.*}", ctx.errs)
@@ -271,6 +275,7 @@
 	// Verify that CreateClasspathElements detects when a fragment's contents are not contiguous and
 	// are separated by a library from another fragment.
 	t.Run("discontiguous separated by fragment", func(t *testing.T) {
+		t.Parallel()
 		ctx := newCtx()
 		elements := java.CreateClasspathElements(ctx, []android.Module{artBaz, myBar, artQuuz, platformFoo}, []android.Module{artFragment, myFragment})
 		expectedElements := java.ClasspathElements{
@@ -285,6 +290,7 @@
 	// Verify that CreateClasspathElements detects when a fragment's contents are not contiguous and
 	// are separated by a standalone library.
 	t.Run("discontiguous separated by library", func(t *testing.T) {
+		t.Parallel()
 		ctx := newCtx()
 		elements := java.CreateClasspathElements(ctx, []android.Module{artBaz, platformFoo, artQuuz, myBar}, []android.Module{artFragment, myFragment})
 		expectedElements := java.ClasspathElements{
@@ -300,6 +306,7 @@
 	// indicates it is from an apex the supplied fragments list does not contain a fragment for that
 	// apex.
 	t.Run("no fragment for apex", func(t *testing.T) {
+		t.Parallel()
 		ctx := newCtx()
 		elements := java.CreateClasspathElements(ctx, []android.Module{artBaz, otherApexLibrary}, []android.Module{artFragment})
 		expectedElements := java.ClasspathElements{