For small positive integer exponents, calculate the result with an inlined loop.

This change may improve the average runtime of JetStream2/raytrace for ~8%.

Change-Id: I0e3939dc9c21b0c392c04d61fd197bf618004ab4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3708024
Commit-Queue: Fanchen Kong <fanchen.kong@intel.com>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81341}