Remove support for multipart/x-mixed-replace

LayoutTests/http/tests/multipart/resources/multipart-nodashes.php

Index: LayoutTests/http/tests/multipart/resources/multipart-nodashes.php
diff --git a/LayoutTests/http/tests/multipart/resources/multipart-nodashes.php b/LayoutTests/http/tests/multipart/resources/multipart-nodashes.php
deleted file mode 100644
index f0891f1e6e97d8903836268dac300247bd8067e5..0000000000000000000000000000000000000000
--- a/LayoutTests/http/tests/multipart/resources/multipart-nodashes.php
+++ /dev/null
@@ -1,10 +0,0 @@
-<?php
-    # Generates a multipart/x-mixed-replace response but doesn't
-    # include the -- before the boundary.
-
-    $boundary = "cutHere";
-    header("Content-Type: multipart/x-mixed-replace; boundary=$boundary");
-    echo("$boundary\r\n");
-    echo("Content-Type: image/png\r\n\r\n");
-    echo(file_get_contents("green-100x100.png"));
-?>