Fixing a memory leak in CompileAndRunModule.

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=wasm-fuzzer
R=jochen@chromium.org,jarin@chromium.org,kcc@chromium.org,machenbach@chromium.org,titzer@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/1738943004

Cr-Commit-Position: refs/heads/master@{#34415}