[LLDB] Add support to resize SVE registers at run-time
We need to resize SVE register based on value received in expedited list.
Also we need to resize SVE registers when we write vg register using
register write vg command. The resize will result in a updated offset
for all of fpr and sve register set. This offset will be configured
in native register context by RegisterInfoInterface and will also be
be updated on client side in GDBRemoteRegisterContext.
A follow up patch will provide a API test to verify this change.
Reviewed By: labath
Differential Revision: https://reviews.llvm.org/D82863