[InstCombine] Don't let folding (select (icmp eq (and X, C1), 0), Y, (or Y, C2))...

[InstCombine] Don't let folding (select (icmp eq (and X, C1), 0), Y, (or Y, C2)) create more instructions than it removes

Summary:
Previously this folding had no checks to see if it was going to result in less instructions. This was pointed out during the review of D34184

This patch adds code to count how many instructions its going to create vs how many its going to remove so we can make a proper decision.

Reviewers: spatel, majnemer

Reviewed By: spatel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34437

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305926 91177308-0d34-0410-b5e6-96231b3b80d8