Changed free(buffer) to delete [] buffer.

This bug (mismatch between new[] and free) was found by running VC++'s /analyze on all of Chrome.

BUG=chromium:427616
LOG=N
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/686193004

Patch from Bruce Dawson <brucedawson@chromium.org>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25003 ce2b1a6d-e550-0410-aec6-3dcde31c8c00