Remove EMCC_SAVE_OPT_TEMP environment variable (#19716)

The files in questions are already save by when `EMCC_DEBUG` (or just
`EMCC_DEBUG_SAVE`) are set.  Having a third options seems rather
pointless.

Furthermore `EMCC_SAVE_OPT_TEMP` doesn't actually work on its own since
it save files into the emscripten temp directory, which is completely
removed unless one of the above options I used.

In addition this code is currently broken due to the expression:

  `int(saved.replace('input', '').replace('.txt', ''))`

It seems like the above code was assuming the intput was of the form
`include<N>.txt` but that is not the case since `saved` is declared on
the line above as:

  `saved = 'save_' + os.path.basename(filename)`

Also remove an unused function from `tools/shared.py`

Author: sbc100

tools/js_optimizer.py

@@ -266,21 +266,9 @@ def write_chunk(chunk, i):
         return temp_file
       filenames = [write_chunk(chunk, i) for i, chunk in enumerate(chunks)]
 
-  if filenames:
-    with ToolchainProfiler.profile_block('run_optimizer'):
-      commands = [config.NODE_JS + [ACORN_OPTIMIZER, f] + passes for f in filenames]
-
-      if os.environ.get('EMCC_SAVE_OPT_TEMP') and os.environ.get('EMCC_SAVE_OPT_TEMP') != '0':
-        for filename in filenames:
-          saved = 'save_' + os.path.basename(filename)
-          while os.path.exists(saved):
-            saved = 'input' + str(int(saved.replace('input', '').replace('.txt', '')) + 1) + '.txt'
-          shutil.copyfile(filename, os.path.join(shared.get_emscripten_temp_dir(), saved))
-
-      filenames = shared.run_multiple_processes(commands, route_stdout_to_temp_files_suffix='js_opt.jo.js')
-
-    for filename in filenames:
-      temp_files.note(filename)
+  with ToolchainProfiler.profile_block('run_optimizer'):
+    commands = [config.NODE_JS + [ACORN_OPTIMIZER, f] + passes for f in filenames]
+    filenames = shared.run_multiple_processes(commands, route_stdout_to_temp_files_suffix='js_opt.jo.js')
 
   with ToolchainProfiler.profile_block('split_closure_cleanup'):
     if closure or cleanup:

tools/scons/site_scons/site_tools/emscripten/emscripten.py

@@ -25,7 +25,7 @@ def generate(env, emscripten_path=None, **kw):
               'EMCC_AUTODEBUG', 'EM_COMPILER_WRAPPER',
               'MOZ_DISABLE_AUTO_SAFE_MODE', 'EMCC_STDERR_FILE',
               'EMSCRIPTEN_SUPPRESS_USAGE_WARNING', 'NODE_PATH', 'EMCC_JSOPT_MIN_CHUNK_SIZE',
-              'EMCC_JSOPT_MAX_CHUNK_SIZE', 'EMCC_SAVE_OPT_TEMP', 'EMCC_CORES', 'EMCC_NO_OPT_SORT',
+              'EMCC_JSOPT_MAX_CHUNK_SIZE', 'EMCC_CORES', 'EMCC_NO_OPT_SORT',
               'EMCC_BUILD_DIR', 'EMCC_DEBUG_SAVE', 'EMCC_SKIP_SANITY_CHECK',
               'EM_PKG_CONFIG_PATH', 'EMCC_CLOSURE_ARGS', 'JAVA_HEAP_SIZE',
               'EMCC_FORCE_STDLIBS', 'EMCC_ONLY_FORCED_STDLIBS', 'EM_PORTS', 'IDL_CHECKS', 'IDL_VERBOSE']:

tools/shared.py

@@ -132,16 +132,6 @@ def get_num_cores():
   return int(os.environ.get('EMCC_CORES', os.cpu_count()))
 
 
-def mp_run_process(command_tuple):
-  cmd, env, route_stdout_to_temp_files_suffix = command_tuple
-  stdout = None
-  if route_stdout_to_temp_files_suffix:
-    stdout = get_temp_files().get(route_stdout_to_temp_files_suffix)
-  subprocess.run(cmd, stdout=stdout, stderr=None, env=env, check=True)
-  if route_stdout_to_temp_files_suffix:
-    return stdout.name
-
-
 def returncode_to_str(code):
   assert code != 0
   if code < 0: