Extract prepareForCcTest

Bug: 182885307
Test: m nothing
Change-Id: Ica17d20775c6dae00978f0f84f768fdaaf55e031
diff --git a/cc/cc_test.go b/cc/cc_test.go
index 205c71f..ab4ef6c 100644
--- a/cc/cc_test.go
+++ b/cc/cc_test.go
@@ -54,6 +54,10 @@
 
 var ccFixtureFactory = android.NewFixtureFactory(
 	&buildDir,
+	prepareForCcTest,
+)
+
+var prepareForCcTest = android.GroupFixturePreparers(
 	PrepareForTestWithCcIncludeVndk,
 	android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
 		variables.DeviceVndkVersion = StringPtr("current")