[lldb] Silence warnings about unused static variables in RegisterInfos_arm64.h

Move them to the only source file that included RegisterInfos_arm64.h
that actually used these variables.

This silences warnings like these:

    In file included from lldb/source/Plugins/Instruction/ARM64/EmulateInstructionARM64.cpp:42:
    lldb/source/Plugins/Process/Utility/RegisterInfos_arm64.h:790:35: warning: ‘g_register_infos_mte’ defined but not used [-Wunused-variable]
      790 | static lldb_private::RegisterInfo g_register_infos_mte[] = {
          |                                   ^~~~~~~~~~~~~~~~~~~~
    lldb/source/Plugins/Process/Utility/RegisterInfos_arm64.h:787:35: warning: ‘g_register_infos_pauth’ defined but not used [-Wunused-variable]
      787 | static lldb_private::RegisterInfo g_register_infos_pauth[] = {
          |                                   ^~~~~~~~~~~~~~~~~~~~~~

Differential Revision: https://reviews.llvm.org/D123206