Make TestContext.RegisterModuleType take an android.ModuleFactory

Avoid having to pass ModuleFactoryAdaptor to every call to
RegisterModuleType in a test by wrapping RegisterModuleType.

Test: all soong tests
Change-Id: If8847d16487de0479cc3020b728256922b3cadba
diff --git a/android/rule_builder_test.go b/android/rule_builder_test.go
index b484811..52c32df 100644
--- a/android/rule_builder_test.go
+++ b/android/rule_builder_test.go
@@ -465,8 +465,8 @@
 		"bar":        nil,
 		"cp":         nil,
 	})
-	ctx.RegisterModuleType("rule_builder_test", ModuleFactoryAdaptor(testRuleBuilderFactory))
-	ctx.RegisterSingletonType("rule_builder_test", SingletonFactoryAdaptor(testRuleBuilderSingletonFactory))
+	ctx.RegisterModuleType("rule_builder_test", testRuleBuilderFactory)
+	ctx.RegisterSingletonType("rule_builder_test", testRuleBuilderSingletonFactory)
 	ctx.Register()
 
 	_, errs := ctx.ParseFileList(".", []string{"Android.bp"})