test: improve test-abort-uncaught-exception

Add `SIGTRAP` to allowed signals (seen on PPC machines in CI).

Improve message when assertion fails in test-abort-uncaught-exception by
providing the signal name that was not expected.

PR-URL: #14013
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

test/abort/test-abort-uncaught-exception.js

@@ -9,7 +9,7 @@ if (process.argv[2] === 'child') {
   throw new Error('child error');
 } else {
   run('', null);
-  run('--abort-on-uncaught-exception', ['SIGABRT', 'SIGILL']);
+  run('--abort-on-uncaught-exception', ['SIGABRT', 'SIGTRAP', 'SIGILL']);
 }
 
 function run(flags, signals) {
@@ -26,7 +26,7 @@ function run(flags, signals) {
         assert.strictEqual(code, 1);
     } else {
       if (signals)
-        assert.strictEqual(signals.includes(sig), true);
+        assert(signals.includes(sig), `Unexpected signal ${sig}`);
       else
         assert.strictEqual(sig, null);
     }