tests: Add gcov support for x86_64 qtest Since x86_64 is a superset of i386 and reuses all its test cases, adopt all the i386 gcov source files as well, substituting their paths appropriately. Signed-off-by: Andreas Färber <afaerber@suse.de> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>