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
diff --git a/android/defaults_test.go b/android/defaults_test.go
index d096b2f..2689d86 100644
--- a/android/defaults_test.go
+++ b/android/defaults_test.go
@@ -80,14 +80,14 @@
 
 	config := TestConfig(buildDir, nil, bp, nil)
 
-	ctx := NewTestContext()
+	ctx := NewTestContext(config)
 
 	ctx.RegisterModuleType("test", defaultsTestModuleFactory)
 	ctx.RegisterModuleType("defaults", defaultsTestDefaultsFactory)
 
 	ctx.PreArchMutators(RegisterDefaultsPreArchMutators)
 
-	ctx.Register(config)
+	ctx.Register()
 
 	_, errs := ctx.ParseFileList(".", []string{"Android.bp"})
 	FailIfErrored(t, errs)
@@ -125,7 +125,7 @@
 	config := TestConfig(buildDir, nil, bp, nil)
 	config.TestProductVariables.Allow_missing_dependencies = proptools.BoolPtr(true)
 
-	ctx := NewTestContext()
+	ctx := NewTestContext(config)
 	ctx.SetAllowMissingDependencies(true)
 
 	ctx.RegisterModuleType("test", defaultsTestModuleFactory)
@@ -133,7 +133,7 @@
 
 	ctx.PreArchMutators(RegisterDefaultsPreArchMutators)
 
-	ctx.Register(config)
+	ctx.Register()
 
 	_, errs := ctx.ParseFileList(".", []string{"Android.bp"})
 	FailIfErrored(t, errs)