[testing] Update max fd limit in test (#35775)

Please see cl/602800790 for details.

Closes #35775

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/35775 from Vignesh2208:test-fix 95d3d93bb9
PiperOrigin-RevId: 603138045

test/core/iomgr/fd_conservation_posix_test.cc

@@ -39,9 +39,9 @@ int main(int argc, char** argv) {
     // set max # of file descriptors to a low value, and
     // verify we can create and destroy many more than this number
     // of descriptors
-    rlim.rlim_cur = rlim.rlim_max = 10;
+    rlim.rlim_cur = rlim.rlim_max = 1000;
     GPR_ASSERT(0 == setrlimit(RLIMIT_NOFILE, &rlim));
-    for (i = 0; i < 100; i++) {
+    for (i = 0; i < 10000; i++) {
       p = grpc_iomgr_create_endpoint_pair("test", nullptr);
       grpc_endpoint_destroy(p.client);
       grpc_endpoint_destroy(p.server);