Torture test 530 fails on mac

[bagder]

The failure is reproducible for me on mac, I can't make it happen on Linux. (The exact iteration that fails isn't always 250)

$ ./runtests.pl -t 530
********* System characteristics ******** 
* curl 7.81.0-DEV (x86_64-apple-darwin20.6.0) 
* libcurl/7.81.0-DEV (SecureTransport) OpenSSL/3.0.0 zlib/1.2.11 brotli/1.0.9 zstd/1.5.0 c-ares/1.18.1 libidn2/2.3.2 nghttp2/1.46.0 librtmp/2.3
* Features: alt-svc AsynchDNS brotli Debug HSTS HTTP2 HTTPS-proxy IDN IPv6 Largefile libz MultiSSL NTLM NTLM_WB SSL TLS-SRP TrackMemory UnixSockets zstd
* Disabled: 
* Host: Daniels-mini2
* System: Darwin Daniels-mini2 21.1.0 Darwin Kernel Version 21.1.0: Wed Oct 13 17:33:23 PDT 2021; root:xnu-8019.41.5~1/RELEASE_X86_64 x86_64
* OS: darwin
* Servers: HTTP-IPv6 HTTP-unix FTP-IPv6 
* Env: 
* Seed: 208179
***************************************** 
test 0530...[multi_socket interface transfer with callbacks returning error]
 251 functions to make fail
** MEMORY FAILURE
Leak detected: memory still allocated: 416 bytes
At 7fb0749048e8, there's 416 bytes.
 allocated by hash.c:73
LIMIT dynbuf.c:98 realloc reached memlimit
 Failed on function number 250 in test.
 invoke with "-t250" to repeat this single case.

 - abort tests
TESTDONE: 1 tests were considered during 17 seconds.
TESTDONE: 0 tests out of 1 reported OK: 0%

TESTFAIL: These test cases failed: 530