Follow-up tweak: Fix IteratorCloseOnException Torque interface

Use same value to rethrow as was used before this change. This doesn't
appear to be explicitly tested anywhere, but the behavior should stay
unchanged nevertheless.

Change-Id: Idaed90a143e9775746f034190918065897094acb
Reviewed-on: https://chromium-review.googlesource.com/c/1329684Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Daniel Clifford <danno@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57472}

src/builtins/builtins-iterator-gen.cc

@@ -198,7 +198,7 @@ void IteratorBuiltinsAssembler::IteratorCloseOnException(
   IteratorCloseOnException(context, iterator, &rethrow, &exception_variable);
 
   BIND(&rethrow);
-  CallRuntime(Runtime::kReThrow, context, exception);
+  CallRuntime(Runtime::kReThrow, context, exception_variable.value());
   Unreachable();
 }