[ragel] Switch to -T1 output instead of -F1

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 #1708

src/Makefile.am

@@ -303,7 +303,7 @@ EXTRA_DIST += \
 # We decided to add ragel-generated files to git...
 #MAINTAINERCLEANFILES += $(RAGEL_GENERATED)
 $(srcdir)/%.hh: $(srcdir)/%.rl
-	$(AM_V_GEN)(cd $(srcdir) && $(RAGEL) -e -F1 -o "$*.hh" "$*.rl") \
+	$(AM_V_GEN)(cd $(srcdir) && $(RAGEL) -e -T1 -o "$*.hh" "$*.rl") \
 	|| ($(RM) "$@"; false)
 
 noinst_PROGRAMS = \