Most modern tools only accept two-dash long options. Remove one-dash
long options which are not recognized by GNU style `getopt_long`.
This ensures long options cannot collide with grouped short options.
Note: llvm-symbolizer has `-demangle={true,false}` for pprof compatibility
(for a while). They are kept.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D106377