Ruby

Fix heap-use-after-free in free_fast_fallback_getaddrinfo_entry (#13231)

This change addresses the following ASAN error:

==36597==ERROR: AddressSanitizer: heap-use-after-free on address 0x512000396ba8 at pc 0x7fcad5cbad9f bp 0x7fff19739af0 sp 0x7fff19739ae8
  WRITE of size 8 at 0x512000396ba8 thread T0
  [643/756] 36600=optparse/test_summary
      #0 0x7fcad5cbad9e in free_fast_fallback_getaddrinfo_entry /home/runner/work/ruby-dev-builder/ruby-dev-builder/ext/socket/raddrinfo.c:3046:22
      #1 0x7fcad5c9fb48 in fast_fallback_inetsock_cleanup /home/runner/work/ruby-dev-builder/ruby-dev-builder/ext/socket/ipsocket.c:1179:17
      #2 0x7fcadf3b611a in rb_ensure /home/runner/work/ruby-dev-builder/ruby-dev-builder/eval.c:1081:5
      #3 0x7fcad5c9b44b in rsock_init_inetsock /home/runner/work/ruby-dev-builder/ruby-dev-builder/ext/socket/ipsocket.c:1289:20
      #4 0x7fcad5ca22b8 in tcp_init /home/runner/work/ruby-dev-builder/ruby-dev-builder/ext/socket/tcpsocket.c:76:12
      #5 0x7fcadf83ba70 in vm_call0_cfunc_with_frame /home/runner/work/ruby-dev-builder/ruby-dev-builder/./vm_eval.c:164:15
...

A struct fast_fallback_getaddrinfo_shared is shared between the main thread and two child threads.
This struct contains an array of fast_fallback_getaddrinfo_entry.

fast_fallback_getaddrinfo_entry and fast_fallback_getaddrinfo_shared were freed separately, and if fast_fallback_getaddrinfo_shared was freed first and then an attempt was made to free a fast_fallback_getaddrinfo_entry, a heap-use-after-free could occur.

This change avoids that possibility by separating the deallocation of the addrinfo memory held by fast_fallback_getaddrinfo_entry from the access and lifecycle of the fast_fallback_getaddrinfo_entry itself.