Fix file descriptor leak in memtest_test_linux_anonymous_maps (#4241)

when we fail opening `/proc`, we need to close the log file fd.

src/debug.c

@@ -1764,7 +1764,10 @@ int memtest_test_linux_anonymous_maps(void) {
     if (!fd) return 0;
 
     fp = fopen("/proc/self/maps","r");
-    if (!fp) return 0;
+    if (!fp) {
+        closeDirectLogFiledes(fd);
+        return 0;
+    }
     while(fgets(line,sizeof(line),fp) != NULL) {
         char *start, *end, *p = line;