After https://crrev.com/c/1172285, abortion and deletion of an
{AsyncCompileJob} is the same. Hence, remove the
{AbortCompileJobsOnIsolate} method and replace all uses by
{DeleteCompileJobsOnIsolate}.

R=ahaas@chromium.org
CC=mstarzinger@chromium.org

Bug: chromium:869420
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I053dc47395a257066bbca55069d53445dc28eeb9
Reviewed-on: https://chromium-review.googlesource.com/1172288Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55092}