The subprocess Service Definition exports SubprocessError with a closed
SUBPROCESS_* code list, rebases SubprocessExecutableNotFoundError on it
with the same name, and adds subprocessSpawnFailure() so consumers that
report a spawn rejection classify ENOENT and other platform errors with
the original as cause. subprocess-local codes empty argv, Windows Job
runner failures, runner IPC failures, and an unloadable node-pty, and
names its pre-aborted spawn error AbortError so the tool registry
classifies it as cancellation.
Win32Error now extends HarnessError with code WIN32_ERROR, keeping its
name, api, and win32Code fields.
Refs #7869
sjw1231
4ef46e21b1