Faster BCP checksum verification.

Avoid opening dex files for updatable BCP components.
Just collect the checksums from jar files using the
`DexFileLoader::GetMultiDexChecksums()` API.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 191828947
Change-Id: Ib737fabc832c56bffef8a98382f689aabe588bd2
1 file changed