Add likely annotation to cmm files in a few obvious places.

Authored by AndreasK on Jan 29 2018, 5:25 PM.

Description

Add likely annotation to cmm files in a few obvious places.

Provide information about paths more likely to be taken in the cmm files
used by the rts.

This leads to slightly better assembly being generated.

Reviewers: bgamari, erikd, simonmar

Subscribers: alexbiehl, rwbarton, thomie, carter

GHC Trac Issues: Trac #14672

Differential Revision: https://phabricator.haskell.org/D4324