Fix tests for node 11 (#28108)

1. Sort is now stable in node 11, which exposed a lack in the sorting of
nested ranges. Ranges now sort based on last ending if the start
positions are the same. This means nested ranges sort the
containing range first, even if a range contains another range that
starts at the same position.
2. Symbol has a new member description which can't be accessed through
the prototype. In addition, Array now has flat and flatMap, which I
excluded to keep baselines the same between Node 6-11.

src/harness/fourslash.ts

@@ -3846,7 +3846,7 @@ ${code}
         }
 
         // put ranges in the correct order
-        localRanges = localRanges.sort((a, b) => a.pos < b.pos ? -1 : 1);
+        localRanges = localRanges.sort((a, b) => a.pos < b.pos ? -1 : a.pos === b.pos && a.end > b.end ? -1 : 1);
         localRanges.forEach((r) => { ranges.push(r); });
 
         return {