Executing a frsp after copysign changes any SNaN inputs
to QNaN which causes test failures.

Change-Id: Ieab5d24fd09344e0a3108565f478fda3b5889556
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3576793Reviewed-by: Junliang Yan <junyan@redhat.com>
Commit-Queue: Milad Farazmand <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/main@{#79866}