Similar to D96617 for llvm-symbolizer.
This patch matches the GNU objdump -d behavior to suppress printing
labels for mapping symbols. Mapping symbol names don't convey much
information.
When --show-all-symbols (not in GNU) is specified, we still print
mapping symbols.
Note: the for (size_t SI = 0, SE = Symbols.size(); SI != SE;) loops
needs to iterate all mapping symbols, even if they are not displayed.
We use the new field IsMappingSymbol to recognize mapping symbols.
This field also enables simplification after D139131.
ELF/ARM/disassemble-all-mapping-symbols.s is enhanced to add .space 2.
If End = std::min(End, Symbols[SI].Addr); is not correctly set, we
would print a .word.
Would IsMappingSymbol be a better name. It would match the form of IsXCOFF and reads a bit better in statements like if (a.IsMappingSymbol) . Not a strong opinion though.