[ELF] Ignore --no-(enum|wchar)-size-warning for ARM/AArch64

[bwerl]

Summary

Adds --no-enum-size-warning and --no-wchar-size-warning to the list of
ignored args for lld. These are valid arguments to GNU ld for
ARM/AArch64, so for compatibility they are now accepted but just
ignored. If the functionality is ever desired, this can be revisited at
that time.

See https://sourceware.org/binutils/docs/ld/ARM.html for more on these
arguments for GNU ld.

[bwerl]

lld/ELF/Options.td

707

Whoops, this should have been FF, same as down below. New patch coming shortly.

lld/ELF/Options.td

 
 // Options listed below are silently ignored for now for compatibility.
 def: Flag<["-"], "d">;
 def: Flag<["-"], "g">;
 def: F<"long-plt">;
 def: FF<"no-add-needed">;
 def: F<"no-copy-dt-needed-entries">;
 def: F<"no-ctors-in-init-array">;
+def: FF<"no-enum-size-warning">;
 def: F<"no-keep-memory">;
 def: F<"no-warn-mismatch">;
+def: FF<"no-wchar-size-warning">;
 def: Separate<["--", "-"], "rpath-link">;
 def: J<"rpath-link=">;
 def: F<"secure-plt">;
 def: F<"sort-common">;
 def: F<"stats">;
 def: F<"warn-execstack">;
 def: F<"warn-once">;
 def: F<"warn-shared-textrel">;

lld/test/ELF/silent-ignore.test

 RUN: ld.lld --version \
 RUN:   -d \
 RUN:   -g \
 RUN:   -long-plt \
 RUN:   --no-add-needed \
 RUN:   -no-copy-dt-needed-entries \
 RUN:   -no-ctors-in-init-array \
+RUN:   --no-enum-size-warning \
 RUN:   -no-keep-memory \
 RUN:   --no-relax \
 RUN:   -no-warn-mismatch \
+RUN:   --no-wchar-size-warning \
 RUN:   -rpath-link . \
 RUN:   -secure-plt \
 RUN:   -sort-common \
 RUN:   -stats \
 RUN:   -warn-execstack \
 RUN:   -warn-once \
 RUN:   -warn-shared-textrel \
 RUN:   -EB \