[test] Remove also_wasm2js btest argument. NFC (#21232)

This only have one user, and we have a cleaner mechanism for doing
this these days in terms of the decorator.

test/common.py

@@ -1912,7 +1912,6 @@ def browser_open(cls, url):
   @classmethod
   def setUpClass(cls):
     super().setUpClass()
-    cls.also_wasm2js = int(os.getenv('EMTEST_BROWSER_ALSO_WASM2JS', '0')) == 1
     cls.port = int(os.getenv('EMTEST_BROWSER_PORT', '8888'))
     if not has_browser() or EMTEST_BROWSER == 'node':
       return
@@ -2156,7 +2155,7 @@ def btest_exit(self, filename, assert_returncode=0, *args, **kwargs):
   def btest(self, filename, expected=None, reference=None,
             reference_slack=0, manual_reference=None, post_build=None,
             args=None, also_proxied=False,
-            url_suffix='', timeout=None, also_wasm2js=False,
+            url_suffix='', timeout=None,
             manually_trigger_reftest=False, extra_tries=1,
             reporting=Reporting.FULL,
             output_basename='test'):
@@ -2197,13 +2196,6 @@ def btest(self, filename, expected=None, reference=None,
     else:
       self.run_browser(outfile + url_suffix, expected=['/report_result?' + e for e in expected], timeout=timeout, extra_tries=extra_tries)
 
-    # Tests can opt into being run under wasmj2s as well
-    # Ignore this under MEMORY64 where wasm2js is not yet supported.
-    if 'WASM=0' not in original_args and (also_wasm2js or self.also_wasm2js) and not self.is_wasm64():
-      print('WASM=0')
-      self.btest(filename, expected, reference, reference_slack, manual_reference, post_build,
-                 original_args + ['-sWASM=0'], also_proxied=False, timeout=timeout)
-
     if also_proxied:
       print('proxied...')
       if reference:

test/test_browser.py

@@ -116,14 +116,14 @@ def decorated(self, *args, **kwargs):
 def also_with_wasm2js(f):
   assert callable(f)
 
-  def metafunc(self, with_wasm2js):
+  def metafunc(self, with_wasm2js, *args, **kwargs):
     assert self.get_setting('WASM') is None
     if with_wasm2js:
       self.require_wasm2js()
       self.set_setting('WASM', 0)
-      f(self)
+      f(self, *args, **kwargs)
     else:
-      f(self)
+      f(self, *args, **kwargs)
 
   metafunc._parameterize = {'': (False,),
                             'wasm2js': (True,)}
@@ -4838,11 +4838,11 @@ def test_fetch_to_memory(self):
   })
   @no_firefox('https://github.com/emscripten-core/emscripten/issues/16868')
   @requires_threads
+  @also_with_wasm2js
   def test_fetch_from_thread(self, args):
     shutil.copyfile(test_file('gears.png'), 'gears.png')
     self.btest_exit('fetch/test_fetch_from_thread.cpp',
-                    args=args + ['-pthread', '-sPROXY_TO_PTHREAD', '-sFETCH_DEBUG', '-sFETCH', '-DFILE_DOES_NOT_EXIST'],
-                    also_wasm2js=True)
+                    args=args + ['-pthread', '-sPROXY_TO_PTHREAD', '-sFETCH_DEBUG', '-sFETCH', '-DFILE_DOES_NOT_EXIST'])
 
   @also_with_wasm2js
   def test_fetch_to_indexdb(self):