Add flags-only CBDT font

[rsheeter]

$ ttx -o - -t cmap fonts/NotoColorEmoji-flagsonly.ttf 
Dumping "fonts/NotoColorEmoji-flagsonly.ttf" to "<stdout>"...
<?xml version="1.0" encoding="UTF-8"?>
<ttFont sfntVersion="\x00\x01\x00\x00" ttLibVersion="4.47">

Dumping 'cmap' table...
  <cmap>
    <tableVersion version="0"/>
    <cmap_format_12 platformID="3" platEncID="10" format="12" reserved="0" length="148" language="0" nGroups="11">
      <map code="0x1f1e6" name="u1F1E6"/><!-- REGIONAL INDICATOR SYMBOL LETTER A -->
      <map code="0x1f1e7" name="u1F1E7"/><!-- REGIONAL INDICATOR SYMBOL LETTER B -->
      <map code="0x1f1e8" name="u1F1E8"/><!-- REGIONAL INDICATOR SYMBOL LETTER C -->
      <map code="0x1f1e9" name="u1F1E9"/><!-- REGIONAL INDICATOR SYMBOL LETTER D -->
      <map code="0x1f1ea" name="u1F1EA"/><!-- REGIONAL INDICATOR SYMBOL LETTER E -->
      <map code="0x1f1eb" name="u1F1EB"/><!-- REGIONAL INDICATOR SYMBOL LETTER F -->
      <map code="0x1f1ec" name="u1F1EC"/><!-- REGIONAL INDICATOR SYMBOL LETTER G -->
      <map code="0x1f1ed" name="u1F1ED"/><!-- REGIONAL INDICATOR SYMBOL LETTER H -->
      <map code="0x1f1ee" name="u1F1EE"/><!-- REGIONAL INDICATOR SYMBOL LETTER I -->
      <map code="0x1f1ef" name="u1F1EF"/><!-- REGIONAL INDICATOR SYMBOL LETTER J -->
      <map code="0x1f1f0" name="u1F1F0"/><!-- REGIONAL INDICATOR SYMBOL LETTER K -->
      <map code="0x1f1f1" name="u1F1F1"/><!-- REGIONAL INDICATOR SYMBOL LETTER L -->
      <map code="0x1f1f2" name="u1F1F2"/><!-- REGIONAL INDICATOR SYMBOL LETTER M -->
      <map code="0x1f1f3" name="u1F1F3"/><!-- REGIONAL INDICATOR SYMBOL LETTER N -->
      <map code="0x1f1f4" name="u1F1F4"/><!-- REGIONAL INDICATOR SYMBOL LETTER O -->
      <map code="0x1f1f5" name="u1F1F5"/><!-- REGIONAL INDICATOR SYMBOL LETTER P -->
      <map code="0x1f1f6" name="u1F1F6"/><!-- REGIONAL INDICATOR SYMBOL LETTER Q -->
      <map code="0x1f1f7" name="u1F1F7"/><!-- REGIONAL INDICATOR SYMBOL LETTER R -->
      <map code="0x1f1f8" name="u1F1F8"/><!-- REGIONAL INDICATOR SYMBOL LETTER S -->
      <map code="0x1f1f9" name="u1F1F9"/><!-- REGIONAL INDICATOR SYMBOL LETTER T -->
      <map code="0x1f1fa" name="u1F1FA"/><!-- REGIONAL INDICATOR SYMBOL LETTER U -->
      <map code="0x1f1fb" name="u1F1FB"/><!-- REGIONAL INDICATOR SYMBOL LETTER V -->
      <map code="0x1f1fc" name="u1F1FC"/><!-- REGIONAL INDICATOR SYMBOL LETTER W -->
      <map code="0x1f1fd" name="u1F1FD"/><!-- REGIONAL INDICATOR SYMBOL LETTER X -->
      <map code="0x1f1fe" name="u1F1FE"/><!-- REGIONAL INDICATOR SYMBOL LETTER Y -->
      <map code="0x1f1ff" name="u1F1FF"/><!-- REGIONAL INDICATOR SYMBOL LETTER Z -->
      <map code="0xfe4e5" name="uFE4E5"/><!-- ???? -->
      <map code="0xfe4e6" name="uFE4E6"/><!-- ???? -->
      <map code="0xfe4e7" name="uFE4E7"/><!-- ???? -->
      <map code="0xfe4e8" name="uFE4E8"/><!-- ???? -->
      <map code="0xfe4e9" name="uFE4E9"/><!-- ???? -->
      <map code="0xfe4ea" name="uFE4EA"/><!-- ???? -->
      <map code="0xfe4eb" name="uFE4EB"/><!-- ???? -->
      <map code="0xfe4ec" name="uFE4EC"/><!-- ???? -->
      <map code="0xfe4ed" name="uFE4ED"/><!-- ???? -->
      <map code="0xfe4ee" name="uFE4EE"/><!-- ???? -->
    </cmap_format_12>
  </cmap>

</ttFont>

$ ttx -l fonts/NotoColorEmoji-flagsonly.ttf 
Listing table info for "fonts/NotoColorEmoji-flagsonly.ttf":
    tag     checksum    length    offset
    ----  ----------  --------  --------
    CBDT  0xE00135EA    906529      5800
    CBLC  0x40057EBD      1204      2164
    GSUB  0x70186CF4      2430      3368
    OS/2  0x760267D7        96       412
    cmap  0x0150CC34       160       508
    head  0x186694AA        54       356
    hhea  0x11640804        36       284
    hmtx  0x09F60000       558      1044
    maxp  0x015A0039        32       220
    name  0x1B5434C3       374       668
    post  0xFB270084        32       252
    vhea  0x0E5E04CA        36       320
    vmtx  0x09C40000       558      1604

[nyshadhr9]

LGTM

[rsheeter]

Note to self: need to update postscript name, update instructions