Don't run FS.createLazyFile tests in WasmFS mode (#19609)

This uses a new decorator to make sure the test runs without WasmFS. That will
unblock us from turning WasmFS on by default (without such annotations, the test
would start to fail once WasmFS was on).

Author: kripken

test/test_browser.py

@@ -92,6 +92,27 @@ def metafunc(self, wasmfs, *args, **kwargs):
   return metafunc
 
 
+# This is similar to @core.no_wasmfs, but it disable WasmFS and runs the test
+# normally. That is, in core we skip the test if we are in the wasmfs.* mode,
+# while in browser we don't have such modes, so we force the test to run without
+# WasmFS.
+#
+# When WasmFS is on by default, these annotations will still be needed. Only
+# when we remove the old JS FS entirely would we remove them.
+def no_wasmfs(note):
+  assert not callable(note)
+
+  def decorator(f):
+    assert callable(f)
+
+    @wraps(f)
+    def decorated(self, *args, **kwargs):
+      self.set_setting('WASMFS', 0)
+      f(self, *args, **kwargs)
+    return decorated
+  return decorator
+
+
 def also_with_wasm2js(f):
   assert callable(f)
 
@@ -1656,6 +1677,7 @@ def test_worker(self):
 
     self.assertContained('you should not see this text when in a worker!', self.run_js('worker.js')) # code should run standalone too
 
+  @no_wasmfs('https://github.com/emscripten-core/emscripten/issues/19608')
   def test_mmap_lazyfile(self):
     create_file('lazydata.dat', 'hello world')
     create_file('pre.js', '''
@@ -1666,6 +1688,7 @@ def test_mmap_lazyfile(self):
     self.emcc_args += ['--pre-js=pre.js', '--proxy-to-worker']
     self.btest_exit(test_file('test_mmap_lazyfile.c'))
 
+  @no_wasmfs('https://github.com/emscripten-core/emscripten/issues/19608')
   @no_firefox('keeps sending OPTIONS requests, and eventually errors')
   def test_chunked_synchronous_xhr(self):
     main = 'chunked_sync_xhr.html'