match_locale() will return false for empty locale string in the PNG
file. Also add a manual test to validate if a PNG file is qualified to
use under recovery.
Bug: 34054052
Test: recovery_manual_test catches invalid PNG files successfully & Locale_test passed
Change-Id: Id7e2136e1d8abf20da15825aa7901effbced8b03
Although O_RDONLY gives the same value as F_OK (0), it's not the right
friend of access(2).
Also clean up the temporary files from ZipTest (TemporaryDir doesn't
like non-empty directory).
Test: recovery_unit_test passes and has no leftover.
Change-Id: I66b90e43c0954c89ce08b36b9e2b4e84183b28f5
Move recovery-refresh/persist tests out because these tests need special
steps to run. Also switch the constants to std::string.
Test: recovery_manual_test passed on an A/B device
Change-Id: I60b3ec6f094044945c3aafc1fae540896a6ddea6