Add isMethodImmutable method to TypedRemapper

I'm going to use this in a new Transformer.

deob/src/main/java/dev/openrs2/deob/remap/TypedRemapper.java

@@ -176,33 +176,32 @@ public final class TypedRemapper extends Remapper {
 		return mapping;
 	}
 
-	private static Map<MemberRef, String> createMethodMapping(ClassPath classPath, DisjointSet<MemberRef> disjointSet) {
-		var mapping = new HashMap<MemberRef, String>();
-		var id = 0;
-
-		for (var partition : disjointSet) {
-			boolean skip = false;
-
+	public static boolean isMethodImmutable(ClassPath classPath, DisjointSet.Partition<MemberRef> partition) {
 		for (var method : partition) {
 			var clazz = classPath.get(method.getOwner());
 
 			if (EXCLUDED_METHODS.contains(method.getName())) {
-					skip = true;
-					break;
+				return true;
 			}
 
 			if (clazz.isDependency()) {
-					skip = true;
-					break;
+				return true;
 			}
 
 			if (clazz.isNative(new MemberDesc(method.getName(), method.getDesc()))) {
-					skip = true;
-					break;
+				return true;
 			}
 		}
 
-			if (skip) {
+		return false;
+	}
+
+	private static Map<MemberRef, String> createMethodMapping(ClassPath classPath, DisjointSet<MemberRef> disjointSet) {
+		var mapping = new HashMap<MemberRef, String>();
+		var id = 0;
+
+		for (var partition : disjointSet) {
+			if (isMethodImmutable(classPath, partition)) {
 				continue;
 			}