Get rid of broken %no-parser, -n, and --no-parser implementation and

Get rid of broken %no-parser, -n, and --no-parser implementation and
documentation.
* TODO: Don't mention them.
* doc/bison.1: Likewise.
* doc/bison.texinfo (Decl Summary): Likewise.
(Bison Options): Likewise.
(Option Cross Key): Likewise.
* src/getargs.c (no_parser_flag): Remove global variable.
(usage): Don't print description of -n and --no-parser.
(long_options): Remove --no-parser entry here.
(getargs): Remove -n case in the switch here.
* src/getargs.h (no_parser_flag): Remove extern.
* tests/regression.at (Web2c Actions): Remove comment that mentions
--no-parser.