This reverts commit 9b05db33.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1708

This reverts commit ae8719eb.

Part of https://github.com/harfbuzz/harfbuzz/issues/1708

Fedora upgraded to ragel 7, which is buggy if char is signed.
Switching to -G2 output fails with sign-compare error:

../../src/hb-buffer-deserialize-json.hh:107:12: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘const char’ [-Werror=sign-compare]
    if ( 9u <= ( (*( p))) && ( (*( p))) <= 13u ) {
         ~~~^~~~~~~~~~~~~

Switching to -T1 for now.  It actually results in smaller code,
at the expense of some binary searching instead of flat tables.
In the not distant future, we might actually generate two different
outputs and choose between depending on size-optimize options.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1708

Sorry for the noise, downstream custom builders.  Please adjust.

Towards possibly using Null pool for some nil objects.

Fixes https://github.com/harfbuzz/harfbuzz/issues/817