Make EqualModules a free function.

Bug: 377723687
Test: Unit tests and compare the ninja and mk files generated.
Change-Id: I7e00f09a15f2857f58bea70bcedc4798630a40bc
diff --git a/cc/cc.go b/cc/cc.go
index 7122bce..9e373ad 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -3705,7 +3705,7 @@
 func ShouldUseStubForApex(ctx android.ModuleContext, parent android.Module, dep android.ModuleProxy) bool {
 	inVendorOrProduct := false
 	bootstrap := false
-	if ctx.EqualModules(ctx.Module(), parent) {
+	if android.EqualModules(ctx.Module(), parent) {
 		if linkable, ok := parent.(LinkableInterface); !ok {
 			ctx.ModuleErrorf("Not a Linkable module: %q", ctx.ModuleName())
 		} else {