Fixed wrong use of to throw that will fail with unexpected v11

I was testing Mocha's compatibility with the upcoming version of Unexpected. For
that version we remove support for satisfy against a function as that has
confused people. I found one test that will fail with the next version as it was
using to throw to satisfy against an error. This test will actually just call
TypeError with the throw error, so it wont really check anything. This PR fixes
the test to assert that the throw error is a TypeError.

test/node-unit/cli/run-helpers.spec.js

@@ -19,7 +19,7 @@ describe('cli "run" command', function() {
       it('should disallow an array of module names', function() {
         expect(
           () => validatePlugin({foo: ['bar']}, 'foo'),
-          'to throw',
+          'to throw a',
           TypeError
         );
       });