remove SIGINT handler for single runs; see #3570

lib/cli/run-helpers.js

@@ -190,22 +190,12 @@ exports.handleFiles = ({
  * @param {Options} [opts] - Options
  * @param {string[]} [opts.files] - List of test files
  * @param {boolean} [opts.exit] - Whether or not to force-exit after tests are complete
+ * @returns {Runner}
  * @private
  */
 exports.singleRun = (mocha, {files = [], exit = false} = {}) => {
   mocha.files = files;
-  const runner = mocha.run(exit ? exitMocha : exitMochaLater);
-
-  process.once('SIGINT', () => {
-    debug('aborting runner');
-    runner.abort();
-
-    // This is a hack:
-    // Instead of `process.exit(130)`, set runner.failures to 130 (exit code for SIGINT)
-    // The amount of failures will be emitted as error code later
-    runner.failures = 130;
-    setImmediate(() => process.kill(process.pid, 'SIGINT'));
-  });
+  return mocha.run(exit ? exitMocha : exitMochaLater);
 };
 
 /**