Use cached |last_vsync_interval_| for double tick check in DelayBasedBeginFrameSource

The interval of |args| and |last_args| in IssueBeginFrameToObserver
may change during runtime due to different throttling policies,
during when there might be unexpected skipping because of the double
tick check. That causes frame-dropping regression.

This CL fixes that by using cached |last_vsync_interval_|, which is
good for both vsync throttling and FrameSink throttling.

Bug: 40280609
Change-Id: I4368dde5224d21a82b4ddc193964d8808bb10042
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5600658
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Jonathan Ross <jonross@chromium.org>
Commit-Queue: Jiahe Zhang <jiahe.zhang@intel.com>
Cr-Commit-Position: refs/heads/main@{#1313245}