This CL adds a builtin which receives an int32 argument and returns the
int32 result. Internally, it checks whether the argument is in the
valid smi range, then calls the runtime function with the smi argument
and converts the return value back from smi to int32.
This saves a lot of code in the wasm TF builder and in Liftoff.

R=mstarzinger@chromium.org

Bug: v8:6600
Change-Id: Icddcb020eae74c767a75090feb4939275432c007
Reviewed-on: https://chromium-review.googlesource.com/1107711
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53946}