Don't create a new module for bp2build conversion.

A performance improvement for bp2build as Blueprint/Soong no longer have
the overhead of additional modules. The creation of these modules
results in:
* traversal of additional modules for each subsequent mutator
* synchronization over a go channel to collect newly created modules:
https://cs.android.com/android/platform/superproject/+/master:build/blueprint/context.go;l=2594,2600;drc=1602226f23181b8c3fbfcaf3358f0297e839d7d3

We avoid both of these by storing the information directly in the
underlying module.

Also as a fringe benefit, removes some necessary boilerplate for
conversion.

For benchmarks, reduces runtime ~1% for 1% converted, ~24% for 100%
converted. See more: go/benchmarks-for-https:-r.android.com-1792714

Test: ran benchmarks/tests in bp2build
Test: build/bazel/ci/bp2build.sh
Change-Id: Ie9273b8cbab5bc6edac1728067ce184382feb211

android/mutator.go

@@ -270,7 +270,7 @@ type TopDownMutatorContext interface {
 	// factory method, just like in CreateModule, but also requires
 	// BazelTargetModuleProperties containing additional metadata for the
 	// bp2build codegenerator.
-	CreateBazelTargetModule(ModuleFactory, string, bazel.BazelTargetModuleProperties, interface{}) BazelTargetModule
+	CreateBazelTargetModule(string, bazel.BazelTargetModuleProperties, interface{})
 }
 
 type topDownMutatorContext struct {
@@ -516,26 +516,24 @@ func registerDepsMutatorBp2Build(ctx RegisterMutatorsContext) {
 }
 
 func (t *topDownMutatorContext) CreateBazelTargetModule(
-	factory ModuleFactory,
 	name string,
 	bazelProps bazel.BazelTargetModuleProperties,
-	attrs interface{}) BazelTargetModule {
+	attrs interface{}) {
 	if strings.HasPrefix(name, bazel.BazelTargetModuleNamePrefix) {
 		panic(fmt.Errorf(
 			"The %s name prefix is added automatically, do not set it manually: %s",
 			bazel.BazelTargetModuleNamePrefix,
 			name))
 	}
-	name = bazel.BazelTargetModuleNamePrefix + name
-	nameProp := struct {
-		Name *string
-	}{
-		Name: &name,
+
+	info := bp2buildInfo{
+		Name:       name,
+		Dir:        t.OtherModuleDir(t.Module()),
+		BazelProps: bazelProps,
+		Attrs:      attrs,
 	}
 
-	b := t.createModuleWithoutInheritance(factory, &nameProp, attrs).(BazelTargetModule)
-	b.SetBazelTargetModuleProperties(bazelProps)
-	return b
+	t.Module().base().addBp2buildInfo(info)
 }
 
 func (t *topDownMutatorContext) AppendProperties(props ...interface{}) {