Sanitize llvm-size help

Sanitize llvm-size help

Remove irrelevant options from standard help output.

New output:

    OVERVIEW: llvm object size dumper

    USAGE: llvm-size [options] <input files>

    OPTIONS:

    Generic Options:

      --help           - Display available options (--help-hidden for more)
      --help-list      - Display list of available options (--help-list-hidden for more)
      --version        - Display the version of this program

    llvm-size Options:

      Specify output format
          -A             - System V format
          -B             - Berkeley format
          -m             - Darwin -m format
      --arch=<string>  - architecture(s) from a Mach-O file to dump
      --common         - Print common symbols in the ELF file.  When using Berkely format, this is added to bss.
      Print size in radix:
          -o             - Print size in octal
          -d             - Print size in decimal
          -x             - Print size in hexadecimal
      --format=<value> - Specify output format
        =sysv          -   System V format
        =berkeley      -   Berkeley format
        =darwin        -   Darwin -m format
      -l               - When format is darwin, use long format to include addresses and offsets.
      --radix=<value>  - Print size in radix
        =8             -   Print size in octal
        =10            -   Print size in decimal
        =16            -   Print size in hexadecimal
      --totals         - Print totals of all objects - Berkeley format only

Differential Revision: https://reviews.llvm.org/D62482

llvm-svn: 362593