Fix buffer overflow in jloptions (#60299)

Co-authored-by: Cody Tapscott <84105208+topolarity@users.noreply.github.com>

Author: vchuravy

src/jloptions.c

@@ -725,9 +725,11 @@ JL_DLLEXPORT void jl_parse_opts(int *argcp, char ***argvp)
                 }
                 jl_options.nthreads = nthreads + nthreadsi;
             }
+            assert(jl_options.nthreadpools == 1 || jl_options.nthreadpools == 2);
             int16_t *ntpp = (int16_t *)malloc_s(jl_options.nthreadpools * sizeof(int16_t));
             ntpp[0] = (int16_t)nthreads;
-            ntpp[1] = (int16_t)nthreadsi;
+            if (jl_options.nthreadpools == 2)
+                ntpp[1] = (int16_t)nthreadsi;
             jl_options.nthreads_per_pool = ntpp;
             break;
         }