PPC: set regress-crbug-482998 as slow test

Bug: 
Change-Id: I72a91c3a7c89730b6f54ecd30743263ff0ab4642
Reviewed-on: https://chromium-review.googlesource.com/746946Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#49060}

test/mjsunit/mjsunit.status

@@ -603,6 +603,7 @@
   # take too long with the simulator.
   'regress/regress-1132': [SKIP],
   'regress/regress-740784': [SKIP],
+  'regress/regress-crbug-482998': [PASS, SLOW],
   'regress/regress-91008': [PASS, SLOW],
   'regress/regress-1257': [PASS, SLOW],
   'harmony/regexp-property-lu-ui': [PASS, SLOW],