Disable regress-crbug-518748 on debug
Disable regress-crbug-518748 on debug

Seems to fail only on V8 Linux - debug - code serializer
(See http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20debug%20-%20code%20serializer/builds/3762)

BUG=chromium:518748
TBR=mstarzinger@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/1294163003 .

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#30233}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh