Move copyright scanner script to tools/

The script is used project-wide in Chromium. It used to be in android_webview/
because it was created as WebView-specific tool, but the kind of check it does
is not actually specific to WebView. And for a long time already it also runs
as part of global presubmit.

BUG=486158

Review URL: https://codereview.chromium.org/1167093004

Cr-Commit-Position: refs/heads/master@{#334196}
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index f776cc5..78d7c2ed 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -1404,8 +1404,8 @@
   original_sys_path = sys.path
   try:
     sys.path = sys.path + [input_api.os_path.join(
-        input_api.PresubmitLocalPath(), 'android_webview', 'tools')]
-    import copyright_scanner
+        input_api.PresubmitLocalPath(), 'tools')]
+    from copyright_scanner import copyright_scanner
   finally:
     # Restore sys.path to what it was before.
     sys.path = original_sys_path