RFR: 8251303: C2: remove unused _site_invoke_ratio and related code from InlineTree

[Charlie Gracie]

Hi,

Please review this change to C2 that removes unused code from InlineTree.
I looked to see which change removed the last use of this code but as far
back in history as I could see it was not used.

Bug: https://bugs.openjdk.java.net/browse/JDK-8251303
Webrev: https://cr.openjdk.java.net/~burban/cgracie/unused_code/webrev0.0/

Sponsor Required: Yes

Test:
   Built on MacOS {release,fastdebug}

Thanks,
Charlie