feat: add expected failure support to node compat test harness

Extend the node compat test config to support expected test failures
with exit code and output pattern matching (using [WILDCARD] syntax).

Platform fields now accept:
- false: skip the test on that OS (existing behavior)
- true (or omit): run normally, expected to pass (existing behavior)
- { "exitCode": N, "output": "pattern" }: run the test but expect it
  to fail with the specified exit code and/or output pattern

Top-level "exitCode" and "output" apply to all platforms unless
overridden by a platform-specific entry.

Co-authored-by: bartlomieju <13602871+bartlomieju@users.noreply.github.com>

Author: Copilot