Remove v8-x87-ports@ from WATCHLIST

The x87 port itself has been gone for awhile.

Bug: v8:7310
Change-Id: I1c938ba93720af361733f2c09dc5f128173b5675
Reviewed-on: https://chromium-review.googlesource.com/935198Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51581}

WATCHLISTS

@@ -106,9 +106,6 @@
       'v8-mips-ports@googlegroups.com',
       'v8-ppc-ports@googlegroups.com',
     ],
-    'ia32': [
-      'v8-x87-ports@googlegroups.com',
-    ],
     'merges': [
       # Only enabled on branches created with tools/release/create_release.py
       # 'v8-merges@googlegroups.com',