Just a fast iteration over bytes written in Torque for Smi number and
non-decimal radix, also only for more than one string character result.

Improve following micro-benchmark by ~75%

Before
toHexString
toHexString-Numbers(Score): 7905000

After
toHexString
toHexString-Numbers(Score): 14419000

Bug: v8:10477
Change-Id: I366092d4d70156ad33830352c1122af8794bea76
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2330221
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69272}