[ValueTracking] Lower dom-conditions-dom-blocks and dom-conditions-max-uses thresholds

[ValueTracking] Lower dom-conditions-dom-blocks and dom-conditions-max-uses thresholds

On some of our benchmarks this change shows about 50% compile time improvement without any noticeable performance difference.

Differential Revision: http://reviews.llvm.org/D13248

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248801 91177308-0d34-0410-b5e6-96231b3b80d8