Use bower paths relative to the domain

This is shorter, and makes it easier to move test files around.

Change-Id: Ife3dcdd66b66a698d71b0fce2bce457410a4dd73
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
index d27a0e5..ff278dc 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
@@ -19,8 +19,8 @@
 <meta name="viewport" content="width=device-width, minimum-scale=1.0, initial-scale=1.0, user-scalable=yes">
 <title>gr-diff</title>
 
-<script src="../../../bower_components/webcomponentsjs/webcomponents-lite.min.js"></script>
-<script src="../../../bower_components/web-component-tester/browser.js"></script>
+<script src="/bower_components/webcomponentsjs/webcomponents-lite.min.js"></script>
+<script src="/bower_components/web-component-tester/browser.js"></script>
 <link rel="import" href="../../../test/common-test-setup.html"/>
 
 <link rel="import" href="gr-diff-host.html">