If the maximum number of memory pages is raised using
--wasm-max-mem-pages, we might allocate more than kMaxInt bytes for
wasm memory. The byte length is stored as int in JSArrayBuffer, hence
this can lead to failures.
Thus, we now additially check against kMaxInt, and fail instantiation
if this check fails.

Drive-by: Add/fix more bounds checks.

R=ahaas@chromium.org
BUG=chromium:724846

Change-Id: Id8e1a1e13e15f4aa355ab9414b4b950510e5e88a
Reviewed-on: https://chromium-review.googlesource.com/509255Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45465}