perf: faster element deletion during matching (#4882)

* perf: faster deletion

* fix: leave the tuple init

tinygrad/codegen/uops.py

@@ -269,8 +269,10 @@ class UOpGraph:
         changed += recurse_cnt
         # NOTE: this changes UOp, so we have to delete caches
         up.vin = tuple(rewrite(x) for x in up.vin)
-        if hasattr(up, "parents"): del up.parents
-        if hasattr(up, "cmp_tuple"): del up.cmp_tuple
+        try: del up.parents
+        except AttributeError: pass
+        try: del up.cmp_tuple
+        except AttributeError: pass
         # replace with cached nodes
         if found:=self.nodes.get(key:=up.tuple()): return found
         self.nodes[key] = up