Exclude AArch64 mapping symbols ($x and $d) for symtab symbolization as
it was done for ARM since D95916 tom bring bots back to green state.
This is implemented by setting SF_FormatSpecific such that
llvm-symbolizer will ignore them, and use this flag to re-implement
llvm-nm --special-syms option which make it work for both targets.
Differential Revision: https://reviews.llvm.org/D98803
Mach-O files don’t have size information about the symbols in the object file
format unlike ELF.
Also add the part of the fix to llvm-nm that was missed with r290001 so
-arch armv7m works.
rdar://25681018
llvm-svn: 293099
Yvan Roux