[benchmark] Increase havlak's stack size (#18274)

After #18191 this started to fail. This program does DFS, so it uses
deep recursive calls.
https://github.com/emscripten-core/emscripten/blob/02cc1eecd81d44e4456aa27a9ebddfe5f54c33e6/test/havlak.cpp#L497

Author: aheejin

test/test_benchmark.py

@@ -849,7 +849,9 @@ def test_skinning(self):
 
   def test_havlak(self):
     src = read_file(test_file('havlak.cpp'))
-    self.do_benchmark('havlak', src, 'Found', shared_args=['-std=c++11'])
+    # This runs many recursive calls (DFS) and thus needs a larger stack
+    self.do_benchmark('havlak', src, 'Found', shared_args=['-std=c++11'],
+                      emcc_args=['-sSTACK_SIZE=1MB'])
 
   def test_base64(self):
     src = read_file(test_file('base64.cpp'))