Now that we've moved to Binder, we only have a few lingering atoi()
usages that are cleaned up in this CL.
Rewrite match_multi_entry() entirely, with tests to verify both old
and new implementations.
Test: adb shell /data/nativetest/vold_tests/vold_tests
Bug: 36655947
Change-Id: Ib79dc1ddc2366db4d5b4e1a1e2ed9456a06a983e