[fuchsia] Create perf-focused fuchsia builder

It still uses cast-receiver, but enables pgo and disables
size-optimization.

After this change, any further tunings can be handled by using
is_fuchsia && !optimize_for_size.

Cq-Include-Trybots: luci.chrome.try:fuchsia-smoke-sherlock
Bug: 407068989
Change-Id: Ia121fc273081addb3520f704e911102f2a97e37d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6463531
Commit-Queue: Haiyang Pan <hypan@google.com>
Auto-Submit: Zijie He <zijiehe@google.com>
Reviewed-by: Haiyang Pan <hypan@google.com>
Cr-Commit-Position: refs/heads/main@{#1456007}