test: make abort-fatal-error more robust

It's saner to check exit codes or signals to determine if the process
actually aborted. On OSX and Linux the exit code is 134, on SunOS it
propagates the SIGABRT signal

test/simple/test-abort-fatal-error.js

@@ -34,6 +34,17 @@ cmdline += ' --max-old-space-size=4 --max-new-space-size=1';
 cmdline += ' -e "a = []; for (i = 0; i < 1e9; i++) { a.push({}) }"';
 
 exec(cmdline, function(err, stdout, stderr) {
-  assert(err);
-  assert(stderr.toString().match(/abort/i));
+  if (!err) {
+    console.log(stdout);
+    console.log(stderr);
+    assert(false, 'this test should fail');
+    return;
+  }
+
+  if (err.code !== 134 || err.signal !== 'SIGABRT') {
+    console.log(stdout);
+    console.log(stderr);
+    console.log(err);
+    assert(false, err);
+  }
 });