Support text ABI dump file format

This commit adds an option to read ABI reference dump in text file
format directly from `prebuilts/abi-dumps`.  If both the text file and
the gzip format exist, an error will be emitted.

Bug: 78650426
Test: create libexif.lsdump.gz and it works as usual
Test: create libexif.lsdump (decompressed) and it works
Test: touch both libexif.lsdump.gz and libexif.lsdump and it errors
Change-Id: I420a5953fb80855cb5c07e5a4d347fb6709f0340