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

android/register.go

@@ -81,10 +81,11 @@ func RegisterPreSingletonType(name string, factory SingletonFactory) {
 
 type Context struct {
 	*blueprint.Context
+	config Config
 }
 
-func NewContext() *Context {
-	ctx := &Context{blueprint.NewContext()}
+func NewContext(config Config) *Context {
+	ctx := &Context{blueprint.NewContext(), config}
 	ctx.SetSrcDir(absSrcDir)
 	return ctx
 }
@@ -157,7 +158,7 @@ type RegistrationContext interface {
 // Extracting the actual registration into a separate RegisterBuildComponents(ctx) function
 // allows it to be used to initialize test context, e.g.
 //
-//   ctx := android.NewTestContext()
+//   ctx := android.NewTestContext(config)
 //   RegisterBuildComponents(ctx)
 var InitRegistrationContext RegistrationContext = &initRegistrationContext{
 	moduleTypes:    make(map[string]ModuleFactory),