[regexp] Add additional test for match indices.

Bug: v8:9548
Change-Id: I0842ca8ce49ea3a831ae4f168c6dfa7d65dfe063
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1930173Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Joshua Litt <joshualitt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65156}

test/mjsunit/harmony/regexp-match-indices.js

@@ -135,3 +135,12 @@
   }
   assertTrue(rec());
 }
+
+// Match between matches.
+{
+  const re = /a+(?<A>zz)?(?<B>ii)?/;
+  const m = re.exec("xaaazzii");
+  assertTrue(/b+(?<C>cccc)?/.test("llllllbbbbbbcccc"));
+  assertEquals(m.indices, [[1, 8], [4, 6], [6, 8]]);
+  assertEquals(m.indices.groups, {'A': [4, 6], 'B': [6, 8]});
+}