IPC fuzzer: fix re2 dependency.
The location of re2.gyp seems to have changed with https://codereview.chromium.org/141053003.

BUG=260848
TBR=brettw@chromium.org

Review URL: https://codereview.chromium.org/144123002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246104 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246104