runtime: use searchIdx in scavengeOne
runtime: use searchIdx in scavengeOne

This is an optimization that prevents N^2 behavior within a chunk, but
was accidentally skipped. There should be no functional change as a
result of this CL.

Fixes #54892.

Change-Id: I861967a2268699fdc3464bd41bc56618b5628e6b
Reviewed-on: https://go-review.googlesource.com/c/go/+/429255
Auto-Submit: Michael Knyszek <4473450dc5c88f06e1fb787f303d7805ec2aee65@google.com>
Reviewed-by: Keith Randall <8c99c3a9284e493be632950b84cd789d08ed3e9d@golang.org>
Reviewed-by: Keith Randall <8c99c3a9284e493be632950b84cd789d08ed3e9d@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Run-TryBot: Michael Knyszek <4473450dc5c88f06e1fb787f303d7805ec2aee65@google.com>

golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go