This is a second attempt at landing CL 644866 which was reverted by
CL 667019.

Extends the current implementation of WASM exceptions to be able to
throw exceptions with values (not just tags).

A JS typed (uint_16) array is used to hold the thrown values. This
allows all WASM types to be stored (i32, i64, f32, and f64) as well as
be inspected in JS.

The previous CL was reverted because the WASM compiler made calls to
run time functions with tagged objects, which must not be done. To fix
this, all run time calls use the thread-level isolate to hold the
exception being processed.

Bug: v8:6577
Change-Id: I4b1ef7e2847b71a2fab8e9934a0531057db9de63
Reviewed-on: https://chromium-review.googlesource.com/677056
Commit-Queue: Karl Schimpf <kschimpf@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Eric Holk <eholk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48148}