[test] Re-enable mjsunit/constant-folding-2 test that no longer fails.

R=jarin@chromium.org
BUG=v8:4506
LOG=n

Review URL: https://codereview.chromium.org/1413503006

Cr-Commit-Position: refs/heads/master@{#31455}

test/mjsunit/mjsunit.status

@@ -160,9 +160,6 @@
   'deopt-with-fp-regs': [PASS, NO_VARIANTS],
   'regress-sync-optimized-lists': [PASS, NO_VARIANTS],
 
-  # TODO(bmeurer/jarin): Crash in code generator?
-  'constant-folding-2': [PASS, NO_VARIANTS],
-
   # issue 4078:
   'allocation-site-info': [PASS, NO_VARIANTS],