Squiz/Heredoc: move a test to its own file

Move the git conflict/parse error test to its own file.

Related to 143

src/Standards/Squiz/Tests/PHP/HeredocUnitTest.1.inc

@@ -10,18 +10,3 @@ My name is "$name". I am printing some $foo->foo.
 Now, I am printing some {$foo->bar[1]}.
 This should not print a capital 'A': \x41
 EOT;
-
-// The following function has a simulated git conflict for testing.
-// This is not a merge conflict - it is a valid test case.
-// Please do not remove.
-function test()
-    {
-        $arr = array(
-            'a' => 'a'
-<<<<<<< HEAD
-            'b' => 'b'
-=======
-            'c' => 'c'
->>>>>>> master
-        );
-    }

src/Standards/Squiz/Tests/PHP/HeredocUnitTest.2.inc

@@ -0,0 +1,17 @@
+<?php
+
+// Intentional parse error.
+// The following function has a simulated git conflict for testing.
+// This is not a merge conflict - it is a valid test case.
+// Please do not remove.
+function test()
+    {
+        $arr = array(
+            'a' => 'a'
+<<<<<<< HEAD
+            'b' => 'b'
+=======
+            'c' => 'c'
+>>>>>>> master
+        );
+    }