Deletes temporary files from thread pool when report is cancel

Bug: 163027506
Test: atest dumpstate_test
Test: atest dumpstate_smoke_test
Test: Manual cancel the bureport from notification.
Change-Id: Ic4ab0531e0f598c2d2b820293cd2e6444bbf1abb
Merged-In: Ic4ab0531e0f598c2d2b820293cd2e6444bbf1abb
(cherry picked from commit 0daac91e7b4b2b9a108be1f57dd77c9813abb90f)
3 files changed