Add a WATCHLIST entry for trap-handler

Changes to the trap-handler directory need special security review. Add
a WATCHLIST to make it less likely that security review is ignored.
The watch list has ahaas and clemensb as V8-side owners and mark and
mseaborn as security reviewers.

R=ahaas@chromium.org, mark@chromium.org, mseaborn@chromium.org

Change-Id: I3af3eee5797d20353c39a33de009f39df85e98a9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4165617
Reviewed-by: Mark Seaborn <mseaborn@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#85355}

WATCHLISTS

@@ -101,6 +101,9 @@
                   '|test/unittests/heap/cppgc/' \
                   '|test/unittests/heap/cppgc-js/',
     },
+    'trap-handler': {
+      'filepath': 'src/trap-handler/',
+    },
   },
 
   'WATCHLISTS': {
@@ -167,5 +170,11 @@
     'cppgc': [
       'oilpan-reviews+v8@chromium.org',
     ],
+    'trap-handler': [
+      'ahaas@chromium.org',
+      'clemensb@chromium.org',
+      'mark@chromium.org',
+      'mseaborn@chromium.org',
+    ],
   },
 }