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

sdk/testing.go

@@ -80,7 +80,7 @@ func testSdkContext(bp string, fs map[string][]byte, extraOsTypes []android.OsTy
 		}
 	}
 
-	ctx := android.NewTestArchContext()
+	ctx := android.NewTestArchContext(config)
 
 	// Enable androidmk support.
 	// * Register the singleton
@@ -129,7 +129,7 @@ func testSdkContext(bp string, fs map[string][]byte, extraOsTypes []android.OsTy
 	ctx.PreDepsMutators(RegisterPreDepsMutators)
 	ctx.PostDepsMutators(RegisterPostDepsMutators)
 
-	ctx.Register(config)
+	ctx.Register()
 
 	return ctx, config
 }