This CL only clears the wasm translations that correspond to the context
group being reset instead of clearing all.

R=clemensh@chromium.org,kozyatinskiy@chromium.org
BUG=chromium:892864

Cq-Include-Trybots: luci.chromium.try:linux_chromium_headless_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Ib5af0489cbdb7c9b1571cb9cf935fda3bee14015
Reviewed-on: https://chromium-review.googlesource.com/c/1292676Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Alexei Filippov <alph@chromium.org>
Commit-Queue: Aseem Garg <aseemgarg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57302}