ada: Binder respects Ada version for checksum of runtime files

ada: Binder respects Ada version for checksum of runtime files

The parsing to compute the checksums of runtime files (within the
binder) was done using the default Ada version (Ada 2012 currently),
while the creation of the checksum, when the runtime files are
compiled, is performed in a more recent Ada version (Ada 2022
currently). This change forces the checksum computation for runtime
files to be done with the same Ada version as when they were created.

gcc/ada/

	* ali-util.adb (Get_File_Checksum): Force the parsing for
	the checksum computation of runtime files to be done in
	the corresponding recent Ada version.