support.run_command ignores --no-fail-fast

Start with scripts/test/support.py, especially run_command, then trace --no-fail-fast handling in check.py and the caller in scripts/test/wasm2js.py. Reproduce the failure with the affected test command and confirm that a failed run_command reports the failure without aborting the full suite when --no-fail-fast is enabled.

When using --no-fail-fast there are some tests that still abort the test suite when they fail. Notably code that uses support.run_command which throws exceptions that are never caught.

Traceback (most recent call last):
  File "/builds/sertonix/aports/community/binaryen/src/binaryen-version_128/check.py", line 488, in <module>
    sys.exit(main())
             ^^^^^^
  File "/builds/sertonix/aports/community/binaryen/src/binaryen-version_128/check.py", line 471, in main
    TEST_SUITES[test]()
  File "/builds/sertonix/aports/community/binaryen/src/binaryen-version_128/check.py", line 422, in wrapper
    result = func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "/builds/sertonix/aports/community/binaryen/src/binaryen-version_128/scripts/test/wasm2js.py", line 163, in test_wasm2js
    test_wasm2js_output()
  File "/builds/sertonix/aports/community/binaryen/src/binaryen-version_128/scripts/test/wasm2js.py", line 126, in test_wasm2js_output
    out = support.run_command(cmd, expected_err='', err_ignore='ExperimentalWarning')
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/builds/sertonix/aports/community/binaryen/src/binaryen-version_128/scripts/test/support.py", line 154, in run_command
    raise Exception(f"run_command `{' '.join(cmd)}` failed ({code}) {err or ''}")
Exception: run_command `/usr/bin/node --experimental-modules --no-warnings --loader /builds/sertonix/aports/community/binaryen/src/binaryen-version_128/scripts/test/node-esm-loader.mjs a.2asm.asserts.mjs` failed (1) 
node:internal/modules/run_main:107
    triggerUncaughtException(
    ^
assertion failed on line 345
(Use `node --trace-uncaught ...` to show where the exception was thrown)
Node.js v24.14.0

I tried at https://github.com/WebAssembly/binaryen/pull/8503 bit it is not a good change.