patchutils.py: Move external test resources to a separate directory.

staging/tests/simple.patch

@@ -0,0 +1,25 @@
+From be07df750862699f2515c0ac0ceb7a6c25e9458a Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Author=20Name?= <author@email.com>
+Subject: [PATCH v3] component: Replace arg1 with arg2.
+
+Signed-off-by: =?UTF-8?q?Author=20Name?= <author@email.com>
+Signed-off-by: Other Developer <other@email.com>
+---
+ test.txt | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/test.txt b/test.txt
+index d54375d..0078e66 100644
+--- a/test.txt
++++ b/test.txt
+@@ -1,7 +1,7 @@
+ line1();
+ line2();
+ line3();
+-function(arg1);
++function(arg2);
+ line5();
+ line6();
+ line7();
+-- 
+2.7.1