Crash on benchmark using recursive flag

[RubenKelevra]

Describe the bug
I tried the benchmark function out with the -r flag. If I use it without the -S parameter, it will crash.

To Reproduce
Steps to reproduce the behavior:

1. Install zstd 1.5.6 under CachyOS
2. Run zstd -b3 -r Pictures with files in Pictures
3. Crash

Expected behavior
No crash

Screenshots and charts

$ zstd -b -r Pictures
zstd: /tmp/pkg/src/zstd-1.5.6/programs/benchzstd.c:150: formatString_u: Assertion `value <= 100' failed.
Caught SIGABRT signal, printing stack:
/usr/lib/libc.so.6(pthread_kill+0x11b) [0x737983a3e65b]
/usr/lib/libc.so.6(gsignal+0x18) [0x7379839df0a8]
/usr/lib/libc.so.6(abort+0xd7) [0x7379839c147b]
/usr/lib/libc.so.6(+0x2439f) [0x7379839c139f]
/usr/lib/libc.so.6(+0x38256) [0x7379839d5256]
zstd(+0xf3bf) [0x600c5e9d53bf]
zstd(+0x7012) [0x600c5e9cd012]
/usr/lib/libc.so.6(+0x2618e) [0x7379839c318e]
/usr/lib/libc.so.6(__libc_start_main+0x8a) [0x7379839c324a]
zstd(+0x9ae5) [0x600c5e9cfae5]
fish: Job 1, 'zstd -b -r Pictures' terminated by signal SIGABRT (Abort)

$ zstd -b3 -S -r Pictures
 3#-04-24 174906.png :     46266 ->     39335 (x1.176),  160.5 MB/s, 7891.5 MB/s
 3#-02-07 214221.png :    213367 ->    201378 (x1.060),  195.9 MB/s, 15163.9 MB/s
 3#-03-20 191943.png :     12871 ->     12445 (x1.034),  526.7 MB/s, 7999.9 MB/s
 3#-02-07 185449.png :    244645 ->    234444 (x1.044),  165.2 MB/s, 11230.8 MB/s
 3#-12-01 180247.png :     31734 ->     30456 (x1.042),  911.0 MB/s  27331.3 MB/s
 3#-11-02 133914.png :   1398892 ->   1398934 (x1.000), 3559.6 MB/s, 25123.0 MB/s
 3#240719_090203.jxl :     43696 ->     43706 (x1.000), 2110.4 MB/s  50011.2 MB/s
 3#240722_203436.jxl :    118656 ->    118668 (x1.000), 2408.6 MB/s, 50026.5 MB/s
 3#-11-01 042456.png :     13843 ->     13380 (x1.035), 1048.6 MB/s, 24124.4 MB/s
[...]

Desktop (please complete the following information):

• OS: CachyOS
• Version 1.5.6-2
• Compiler / Build system: Link
• Flags: CachyOS uses -O3 with x86_64 v4 optimizations
• Other relevant hardware specs: Intel i5-1135G7

[Cyan4973]

Indeed, the current code limits benchmark to ~100 files.
But it's just a display limit.
I think it can be extended.