Removing unused page_set data.

BUG=435174

Review URL: https://codereview.chromium.org/744893002

Cr-Commit-Position: refs/heads/master@{#305064}

tools/perf/page_sets/data/calendar_forward_backward.json

-{
-    "description": "Describes the Web Page Replay archives for a page set. Don't edit by hand! Use record_wpr for updating.", 
-    "archives": {
-        "calendar_forward_backward_000.wpr": [
-            "https://www.google.com/calendar/"
-        ]
-    }
-}

tools/perf/page_sets/data/calendar_forward_backward_000.wpr.sha1

-9633da77e5cdd216ca966a1357b7500d522e8583
\ No newline at end of file