test(e2e): gate signal/timeout scripts on unix-shell — POSIX-only semantics, documented Windows limitation

Author: Sunrisepeak

tests/e2e/158_test_signal_and_duration.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# requires:
+# requires: unix-shell
 # Signaled tests report shell-convention exit codes (128+sig) with the signal
 # number in JSON, and every JSON test record carries duration_ms.
 set -e

tests/e2e/160_test_timeout.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# requires:
+# requires: unix-shell
 # `mcpp test --timeout <secs>`: a hung test is killed and reported as a
 # timeout failure; the rest of the suite still runs.
 set -e