Add a field to indicate the background dexopt pass.

Bug: 242170869
Test: m
(cherry picked from https://android-review.googlesource.com/q/commit:ed63ebaea41df969bfd25b5dc93611c954d86e0e)
Merged-In: Id2911a93a8dedd6323cfb2e7f264ea64123199de
Change-Id: Id2911a93a8dedd6323cfb2e7f264ea64123199de