[Icons] Remove btn_toolbar_reload.png and test_ic_refresh_black_24dp

Update `btn_toolbar_reload` as a drawable alias. Since refresh is not
automirrored, create `ic_refresh_24dp_rtl.xml` to keep it mirrored in
RTL locale. This allows us to remove all the png version of
btn_toolbar_reload.

Also remove the test only resource that doesn't seem necessary
test_ic_refresh_black_24dp.xml.

Bug: 465841381
Change-Id: I4d936216bee75a493689f4c3f840178275cadc84
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7256663
Commit-Queue: Wenyu Fu <wenyufu@chromium.org>
Reviewed-by: Joel Tan-Aristy <jtanaristy@google.com>
Cr-Commit-Position: refs/heads/main@{#1558360}