add --legacy to fm, legacy=true to fm_bot

E.g.

    ~/skia (make-from-memory↑2|●1…) $ cat test.sh
    #!/bin/bash

    set -e
    set -x

    WHERE=${1:-foo}

    ninja -C out fm

    rm -rf $WHERE
    mkdir -p $WHERE

    cat <<EOF | go run tools/fm/fm_bot.go -processLimit 0 -quiet -script - out/fm
        b=cpu gms ct=8888 w=$WHERE/8888 legacy=true
        b=cpu gms ct=8888 w=$WHERE/srgb
        b=cpu gms ct=565  w=$WHERE/565
        b=cpu gms ct=f16  w=$WHERE/f16
    EOF

    ~/skia (make-from-memory↑2|●1…) $ time ./test.sh
    + WHERE=foo
    + ninja -C out fm
    ninja: Entering directory `out'
    ninja: no work to do.
    + rm -rf foo
    + mkdir -p foo
    + cat
    + go run tools/fm/fm_bot.go -processLimit 0 -quiet -script - out/fm
           11.81 real       318.92 user        14.51 sys

    ~/skia (make-from-memory↑2|●1…) $ idiff foo/8888/ foo/srgb/
    671 files are identical.
    25 diffs written to diff.html

Change-Id: I01fe1ceeada971d8d18efc11961b9f753624fcf2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/205830
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
1 file changed