Pass Config to NewTestContext instead of ctx.Register

Prepare for using Config when adding singletons by passing
Config to NewTestContext and NewContext instead of to ctx.Register.
This will enable a followup change to store SingletonMakeVarsProviders
registered on the Context in the Config, which is necessary to run
multiple tests in parallel without data races.

Test: all soong tests
Change-Id: Id229629a4e42ff4487d317241673837726c075fc

python/python_test.go

@@ -329,13 +329,13 @@ func TestPythonModule(t *testing.T) {
 	for _, d := range data {
 		t.Run(d.desc, func(t *testing.T) {
 			config := android.TestConfig(buildDir, nil, "", d.mockFiles)
-			ctx := android.NewTestContext()
+			ctx := android.NewTestContext(config)
 			ctx.PreDepsMutators(RegisterPythonPreDepsMutators)
 			ctx.RegisterModuleType("python_library_host", PythonLibraryHostFactory)
 			ctx.RegisterModuleType("python_binary_host", PythonBinaryHostFactory)
 			ctx.RegisterModuleType("python_defaults", defaultsFactory)
 			ctx.PreArchMutators(android.RegisterDefaultsPreArchMutators)
-			ctx.Register(config)
+			ctx.Register()
 			_, testErrs := ctx.ParseBlueprintsFiles(bpFile)
 			android.FailIfErrored(t, testErrs)
 			_, actErrs := ctx.PrepareBuildActions(config)