base: Adding multi-letter command support to GDB stub

The GDB remote protocol defines multi-letter
 command names that start with a "v".
I added vKill and vMustReplyEmpty as an example.

Change-Id: I10177729c7d6a3e7d469ce66a63bfcfd21aa6f83
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/63525
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
2 files changed