Fix __halt_compiler() pretty printing edge case

We can't strip the <?php at the end of a __halt_compiler() segment
in file mode.

Fixed by being a bit more explicit in prettyPrintFile() about what
we want to do...

lib/PhpParser/PrettyPrinterAbstract.php

@@ -125,15 +125,22 @@ public function prettyPrintExpr(Expr $node) {
      * @return string Pretty printed statements
      */
     public function prettyPrintFile(array $stmts) {
-        $p = rtrim($this->prettyPrint($stmts));
+        if (!$stmts) {
+            return "<?php\n\n";
+        }
 
-        $p = preg_replace('/^\?>\n?/', '', $p, -1, $count);
-        $p = preg_replace('/<\?php$/', '', $p);
+        $p = $this->prettyPrint($stmts);
 
-        if (!$count) {
+        if ($stmts[0] instanceof Stmt\InlineHTML) {
+            $p = preg_replace('/^\?>\n?/', '', $p);
+        } else {
             $p = "<?php\n\n" . $p;
         }
 
+        if ($stmts[count($stmts) - 1] instanceof Stmt\InlineHTML) {
+            $p = preg_replace('/<\?php$/', '', rtrim($p));
+        }
+
         return $p;
     }
 

test/code/prettyPrinter/stmt/haltCompiler.file-test

@@ -0,0 +1,27 @@
+__halt_compiler
+-----
+<?php
+
+echo 'foo';
+__halt_compiler();
+!!!
+???
+-----
+<?php
+
+echo 'foo';
+__halt_compiler();
+!!!
+???
+-----
+<?php
+
+echo 'foo';
+__halt_compiler();
+<?php
+-----
+<?php
+
+echo 'foo';
+__halt_compiler();
+<?php