cc bazel handlers: use better interface checking

This is a far better approach for ensuring that bazel handlers implement
the BazelHandler interface, as it causes a compile error if they do not
implement the appropriate interface methods.

Test: Manually verified no change in ninja file
Change-Id: I63a4f8b57e3aedd4c0915c2fd2eb7029e9a993aa

cc/object.go

@@ -47,11 +47,11 @@ type objectLinker struct {
 }
 
 type objectBazelHandler struct {
-	BazelHandler
-
 	module *Module
 }
 
+var _ BazelHandler = (*objectBazelHandler)(nil)
+
 func (handler *objectBazelHandler) QueueBazelCall(ctx android.BaseModuleContext, label string) {
 	bazelCtx := ctx.Config().BazelContext
 	bazelCtx.QueueBazelRequest(label, cquery.GetOutputFiles, android.GetConfigKey(ctx))