Handle intermittent failure of brk with ENOMEM

This seems ridiculous but it has happened on CI and it doesn't look like our fault.
https://productionresultssa12.blob.core.windows.net/actions-results/45e0fad4-3a0f-4a69-b11c-5663a1815bc8/workflow-job-run-567a1046-b6a4-5b6c-0182-4dc5e6161b5b/logs/job/job-logs.txt?rsct=text%2Fplain&se=2024-09-08T08%3A07%3A04Z&sig=oOdt6lxVIcfUQrU9s4GUfJLgwDuNVcPP5YBa9siAH94%3D&ske=2024-09-08T18%3A18%3A12Z&skoid=ca7593d4-ee42-46cd-af88-8b886a2f84eb&sks=b&skt=2024-09-08T06%3A18%3A12Z&sktid=398a6654-997b-47e9-b12b-9515b896b4de&skv=2024-05-04&sp=r&spr=https&sr=b&st=2024-09-08T07%3A56%3A59Z&sv=2024-05-04

src/test/brk.c

@@ -6,12 +6,25 @@ int main(void) {
  void* prev;
  void* start = sbrk(0);
  test_assert((intptr_t)start != -1);
- test_assert(start == sbrk(111));
+ void* start_after_allocation = sbrk(111);
+ if (start_after_allocation == (void*)-1) {
+ // We have seen an intermittent failure here on 32-bit :-(
+ test_assert(errno == ENOMEM);
+ test_assert(sizeof(void*) == 4);
+ atomic_puts("EXIT-SUCCESS");
+ return 0;
+ }
 
+ test_assert(start == start_after_allocation);
  memset(start, 0xaa, 111);
 
  prev = sbrk(1000000);
- test_assert(prev != (void*)-1);
+ if (prev == (void*)-1) {
+ test_assert(errno == ENOMEM);
+ test_assert(sizeof(void*) == 4);
+ atomic_puts("EXIT-SUCCESS");
+ return 0;
+ }
  test_assert(0 == brk(prev));
 
  atomic_puts("EXIT-SUCCESS");