remove pingsender from Tor Browser

In https://bugzilla.mozilla.org/show_bug.cgi?id=1310703 (for Firefox 54), Mozilla added a pingsender executable that uses libcurl to send telemetry info when a crash occurs. While we disable telemetry by pref, for defense-in-depth against a potential proxy bypass we should stop shipping the pingsender executable.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information