As reported in PR21166, there are Intel processors out there that support
rdrand but not rdseed. The fix is to verify both features separately and only
run rdrand/rdseed tests if supported.
gdb/testsuite/ChangeLog:
2017-02-23 Luis Machado <lgustavo@codesourcery.com>
* gdb.reverse/insn-reverse.x86.c (check_rdrand_support): Renamed to ...
(check_supported_features): ... this. Changed return type to void.
(supports_rdseed): New static global.
(rdseed): Check supports_rdseed.
(initialize): Call check_supported_features.
