Fix a typo in bisect-builds.py.

Windows archives extract out into a directory called chrome-win. There
is no chrome-winp directory.

TBR=robertocn@chromium.org

Change-Id: Ia5ee2725e107f32c44105ca396e28a4c0a06844c
Reviewed-on: https://chromium-review.googlesource.com/c/1313731
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606868}

tools/bisect-builds.py

@@ -235,7 +235,7 @@ class PathContext(object):
       if self.platform == 'chromeos':
         extract_dir = 'chrome-chromeos'
       elif self.platform in ('win', 'win64'):
-        extract_dir = 'chrome-winp'
+        extract_dir = 'chrome-win'
 
     return os.path.join(extract_dir, self._binary_name)