Parallelize other.test_no_nuthing for faster runtime. (#25020)

Before:

```
Ran 1 test in 47.265s
```

After:
```
Total core time: 52.263s. Wallclock time: 16.743s. Parallelization: 3.12x.
```

Author: juj

test/test_other.py

@@ -7037,43 +7037,40 @@ def test_no_filesystem_libcxx(self):
     self.set_setting('FILESYSTEM', 0)
     self.do_runf('hello_libcxx.cpp', 'hello, world!')
 
-  @is_slow_test
-  def test_no_nuthin(self):
-    # check FILESYSTEM is automatically set, and effective
-
-    def test(opts, absolute):
-      print('opts, absolute:', opts, absolute)
-      sizes = {}
+  # Verifies that filesystem is automatically omitted, and can be
+  # manually disabled too, and both improve code size.
+  @parameterized({
+    'no_assertions': (['-sASSERTIONS=0'], 120000),
+    'o1': (['-O1'], 91000),
+    'o2': (['-O2'], 46000),
+    'o3_closure': (['-O3', '--closure=1'], 17000),
+    # -Wno-closure is needed due to https://github.com/google/closure-compiler/issues/4108
+    'o3_closure_js': (['-O3', '--closure=1', '-Wno-closure', '-sWASM=0'], 36000),
+    'o3_closure2_js': (['-O3', '--closure=2', '-Wno-closure', '-sWASM=0'], 33000), # might change now and then
+  })
+  def test_no_filesystem_code_size(self, opts, absolute):
+    print('opts, absolute:', opts, absolute)
+    sizes = {}
 
-      def do(name, source, moar_opts):
-        self.clear()
-        # pad the name to a common length so that doesn't effect the size of the
-        # output
-        padded_name = name + '_' * (20 - len(name))
-        self.run_process([EMCC, test_file(source), '-o', padded_name + '.js'] + self.get_cflags() + opts + moar_opts)
-        sizes[name] = os.path.getsize(padded_name + '.js')
-        if os.path.exists(padded_name + '.wasm'):
-          sizes[name] += os.path.getsize(padded_name + '.wasm')
-        self.assertContained('hello, world!', self.run_js(padded_name + '.js'))
-
-      do('normal', 'hello_world_fopen.c', [])
-      do('no_fs', 'hello_world.c', []) # without fopen, we should auto-detect we do not need full fs support and can do FILESYSTEM=0
-      do('no_fs_manual', 'hello_world.c', ['-sFILESYSTEM=0'])
-      print('  ', sizes)
-      self.assertLess(sizes['no_fs'], sizes['normal'])
-      self.assertLess(sizes['no_fs'], absolute)
-      # manual can usually remove a tiny bit more
-      self.assertLess(sizes['no_fs_manual'], sizes['no_fs'] + 30)
-
-    test(['-sASSERTIONS=0'], 120000) # we don't care about code size with assertions
-    test(['-O1'], 91000)
-    test(['-O2'], 46000)
-    test(['-O3', '--closure=1'], 17000)
-    # js too
-    # -Wclosure is needed due to
-    # https://github.com/google/closure-compiler/issues/4108
-    test(['-O3', '--closure=1', '-Wno-closure', '-sWASM=0'], 36000)
-    test(['-O3', '--closure=2', '-Wno-closure', '-sWASM=0'], 33000) # might change now and then
+    def do(name, source, moar_opts):
+      self.clear()
+      # pad the name to a common length so that doesn't effect the size of the
+      # output
+      padded_name = name + '_' * (20 - len(name))
+      self.run_process([EMCC, test_file(source), '-o', padded_name + '.js'] + self.get_cflags() + opts + moar_opts)
+      sizes[name] = os.path.getsize(padded_name + '.js')
+      if os.path.exists(padded_name + '.wasm'):
+        sizes[name] += os.path.getsize(padded_name + '.wasm')
+      self.assertContained('hello, world!', self.run_js(padded_name + '.js'))
+
+    do('normal', 'hello_world_fopen.c', [])
+    do('no_fs', 'hello_world.c', []) # without fopen, we should auto-detect we do not need full fs support and can do FILESYSTEM=0
+    do('no_fs_manual', 'hello_world.c', ['-sFILESYSTEM=0'])
+    print('  ', sizes)
+    self.assertLess(sizes['no_fs'], sizes['normal'])
+    self.assertLess(sizes['no_fs'], absolute)
+    # manual can usually remove a tiny bit more
+    self.assertLess(sizes['no_fs_manual'], sizes['no_fs'] + 30)
 
   def test_no_main_loop(self):
     MAINLOOP = 'var MainLoop'