Allow Node.js to format exceptions.

Do this instead of trying to comment out stack traces. The program will
exit non-zero, so the test runner will always mark it as a failed test.
The `Bail out!` is TAP compliant, so the failure will be apparent in a
log of a test run.

redux/scaffold.js

@@ -72,7 +72,7 @@ module.exports = function (count, test) {
                 } else {
                     stream.write('Bail out!\n')
                     if (error.stack) {
-                        assert.say(error.stack)
+                        throw error
                     } else {
                         assert.inspect(error)
                     }
@@ -114,6 +114,17 @@ module.exports = function (count, test) {
             stream.write('1..' + expected + '\n')
         }
 
+        // Found where line numbers are added, syntax context is added. Will
+        // have to read carefully to see if we can recreate, but then it would
+        // be Node.js/V8 specific, specific to Node.js. Although I have no
+        // intention of running in other JavaScript environments, it is probably
+        // best to treat the Proof scaffold as a minimal process wrapper, let
+        // Node.js do its thing.
+        //
+        // https://github.com/nodejs/node/blob/4db97b832b2522551d1bfacc1b95e3cbbf2df097/src/node.cc#L1440
+        // Hoplessness. Add answer.
+        // http://stackoverflow.com/questions/13746831/how-can-i-get-the-line-number-of-a-syntaxerror-thrown-by-requireid-in-node-js
+        // So, I'm removing a try/catch block here.
         try {
             test.call(null, assert, callback)
             if (test.length == 1) callback()

t/proof/scaffold.t.js

@@ -92,13 +92,14 @@ function prove (assert) {
 
     assert(out.read().toString(), 'Bail out!\n# 1\n', 'throw integer')
 
-    var expected = { exitCode: 1, message: 'exit 1 throw error' }
-
-    scaffold(0, function (_assert) {
-        throw new Error('hello')
-    })(globals, out, exit, noop)
-
-    assert(/^# .*hello$/m.test(out.read().toString()), 'throw error')
+    try {
+        scaffold(0, function (_assert) {
+            throw new Error('hello')
+        })(globals, out, exit, noop)
+    } catch (error) {
+        assert(error.message, 'hello', 'throw error')
+        assert(out.read().toString(), 'Bail out!\n', 'throw error bail out')
+    }
 
     var expected = { exitCode: 1, message: 'exit 1 missing tests' }