[lldb] [ABI] Apply AugmentRegisterInfo() to DynamicRegisterInfo::Registers

Call ABI::AugmentRegisterInfo() once with a vector of all defined
registers rather than calling it for every individual register.  Move
and rename RemoteRegisterInfo from gdb-remote to
DynamicRegisterInfo::Register, and use this class when augmenting
registers.

Differential Revision: https://reviews.llvm.org/D111142