This reverts commit 1f99c66b.

Reason for revert: Test timeouts on Win64 Debug: https://build.chromium.org/p/client.v8/builders/V8%20Win64%20-%20debug/builds/19226

Original change's description:
> [wasm] always allocate memory when guard regions are needed
> 
> When using trap handlers, memory references do not get any checks inserted. This
> means there is no check for a null memory as happens when the memory size is
> 0. Normally this would be correctly caught as an out of bounds access, since the
> low memory addresses are not normally mapped. However, if they were mapped for
> some reason, we would not catch the out of bounds access.
> 
> The fix is to ensure WebAssembly instances always have a guard region even if
> the memory is size 0.
> 
> Bug: chromium:769637
> Change-Id: I2d0f8c107563236c3780eb7746c2f820e319c65f
> Reviewed-on: https://chromium-review.googlesource.com/693137
> Reviewed-by: Mircea Trofin <mtrofin@chromium.org>
> Commit-Queue: Eric Holk <eholk@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#48240}

TBR=gdeepti@chromium.org,mtrofin@chromium.org,eholk@chromium.org

Change-Id: I4065b367c6cfffe8dd601b67cd53ad54759ae96a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:769637
Reviewed-on: https://chromium-review.googlesource.com/692918Reviewed-by: Eric Holk <eholk@chromium.org>
Commit-Queue: Eric Holk <eholk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48242}