[Inliner] Do not apply any bonus for cold callsites.

Summary:
Inlining threshold is increased by application of bonuses when the
callee has a single reachable basic block or is rich in vector
instructions. Similarly, inlining cost is reduced by applying a large
bonus when the last call to a static function is considered for
inlining. This patch disables the application of these bonuses when the
callsite or the callee is cold. The intention here is to prevent a large
cold callsite from being inlined to a non-cold caller that could prevent
the caller from being inlined. This is especially important when the
cold callsite is a last call to a static since the associated bonus is
very high.

Reviewers: chandlerc, davidxl

Subscribers: danielcdh, llvm-commits

Differential Revision: https://reviews.llvm.org/D35823

llvm-svn: 309441