Move CreateTestContext to cc/testing.go

Allow CreateTestContext to be called by tests in other packages
that need cc modules.

Test: all soong tests
Change-Id: I6be04dec50632baa8cb51e55ba14d0ddc0df60b8
diff --git a/cc/prebuilt_test.go b/cc/prebuilt_test.go
index 7cc2651..98d78e8 100644
--- a/cc/prebuilt_test.go
+++ b/cc/prebuilt_test.go
@@ -70,7 +70,7 @@
 
 	config := android.TestArchConfig(buildDir, nil)
 
-	ctx := createTestContext(t, config, bp, fs, android.Android)
+	ctx := CreateTestContext(bp, fs, android.Android)
 
 	ctx.RegisterModuleType("cc_prebuilt_library_shared", android.ModuleFactoryAdaptor(prebuiltSharedLibraryFactory))
 	ctx.RegisterModuleType("cc_prebuilt_library_static", android.ModuleFactoryAdaptor(prebuiltStaticLibraryFactory))