mask stretching differs custom placeholders and regular placeholders

That's like #3165 but with custom placeholder (e.g. ?1) or explicit ranges.

When --mask='?l123' --min-length=4 --max-length=5 produces ?l123 and ?l?l123. Replace ?l with ?1 and add --1='?l', it produces ?1123 and '?11233'. Same with explicit ranges.

I bump into that quite often when I stretch masks with constant suffix and try to reduce charset in ranges based on cracks.

Examples:

$ ./JohnTheRipper/run/john --stdout --mask='?l123' --min-length=4 --max-length=5
0p 0:00:00:00 0.00% (4) 0p/s
a123
[...]
q123
26p 0:00:00:00 3.70% (5) (ETA: 00:20:39) 371.4p/s q123
aa123
[...]
qq123
702p 0:00:00:00 100.00% (5) (2019-10-13 00:20) 10028p/s qq123

$ ./JohnTheRipper/run/john --stdout --mask='?1123' --min-length=4 --max-length=5 --1='?l'
0p 0:00:00:00 0.00% (4) 0p/s
a123
[...]
q123
26p 0:00:00:00 50.00% (5) (ETA: 00:20:51) 520.0p/s q123
a1233
q1233
52p 0:00:00:00 100.00% (5) (2019-10-13 00:20) 1040p/s q1233

$ ./JohnTheRipper/run/john --stdout --mask='[a-z]123' --min-length=4 --max-length=5
0p 0:00:00:00 0.00% (4) 0p/s
a123
[...]
z123
26p 0:00:00:00 50.00% (5) (ETA: 00:30:12) 260.0p/s z123
a1233
[...]
z1233
52p 0:00:00:00 100.00% (5) (2019-10-13 00:30) 520.0p/s z1233

john is quite fresh (has opencl; openmp is disabled):

Version: 1.9.0-jumbo-1+bleeding-ea33667eb 2019-09-23 12:43:34 +0200
Build: linux-gnu 64-bit x86_64 AVX2 AC