Made stack patch test less brittle.

src/coffee-script.coffee

@@ -100,7 +100,7 @@ exports.run = (code, options = {}) ->
   # Compile.
   if not helpers.isCoffee(mainModule.filename) or require.extensions
     answer = compile code, options
-    code = answer.js? and answer.js or answer
+    code = answer.js ? answer
 
   mainModule._compile code, mainModule.filename
 

test/error_messages.coffee

@@ -45,7 +45,7 @@ test "compiler error formatting", ->
 
 test "patchStackTrace line patching", ->
   err = new Error 'error'
-  ok err.stack.indexOf('test/error_messages.coffee:47:4') >= 0 # should be fixed to the correct line if more lines added to this file
+  ok err.stack.match /test\/error_messages\.coffee:\d+:\d+\b/
 
 fs = require 'fs'