jit: use correct type when checking for max value (#73)

eb42305f (jit: avoid integer wraparound in stack size definition (#42),
2021-11-19) introduces a check to avoid an integer overflow when
allocating stack size for JIT.

Unfortunately the maximum value was using PCRE2_SIZE_MAX, eventhough
the variable is of type size_t, so correct it.

Practically; the issue shouldn't affect the most common configurations
where both values are the same, and it will be unlikely that there would
be a configuration where PCRE2_SIZE_MAX > SIZE_MAX, hence the mistake
is unlikely to have reintroduced the original bug and this change should
be therefore mostly equivalent.

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>

src/pcre2_jit_misc.c

@@ -135,7 +135,7 @@ return NULL;
 
 pcre2_jit_stack *jit_stack;
 
-if (startsize == 0 || maxsize == 0 || maxsize > PCRE2_SIZE_MAX - STACK_GROWTH_RATE)
+if (startsize == 0 || maxsize == 0 || maxsize > SIZE_MAX - STACK_GROWTH_RATE)
   return NULL;
 if (startsize > maxsize)
   startsize = maxsize;