Increase "try/android-desktop-x64-rel" CQ experimental to 100%

The builder works fine at 60%, and there are still roughly 50% rooms
in host GCEs pool. After enabling 100% for one day, we will replace
the current compile-only CQ builder with this builder, and move the
GCE bots as well.

Bug: 391893869
Change-Id: Iebe5641c4acfae01691b3549c7e4a9c0e9f43d1d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6282631
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Commit-Queue: Haiyang Pan <hypan@google.com>
Cr-Commit-Position: refs/heads/main@{#1422651}