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/namespace_test.go b/android/namespace_test.go
index 20241fe..90058e3 100644
--- a/android/namespace_test.go
+++ b/android/namespace_test.go
@@ -637,9 +637,9 @@
 
 	ctx = NewTestContext()
 	ctx.MockFileSystem(bps)
-	ctx.RegisterModuleType("test_module", ModuleFactoryAdaptor(newTestModule))
-	ctx.RegisterModuleType("soong_namespace", ModuleFactoryAdaptor(NamespaceFactory))
-	ctx.RegisterModuleType("blueprint_test_module", newBlueprintTestModule)
+	ctx.RegisterModuleType("test_module", newTestModule)
+	ctx.RegisterModuleType("soong_namespace", NamespaceFactory)
+	ctx.Context.RegisterModuleType("blueprint_test_module", newBlueprintTestModule)
 	ctx.PreArchMutators(RegisterNamespaceMutator)
 	ctx.PreDepsMutators(func(ctx RegisterMutatorsContext) {
 		ctx.BottomUp("rename", renameMutator)