Change if-conversion to keep track of the extra cost due to microcoded

Change if-conversion to keep track of the extra cost due to microcoded
instructions separately from the count of non-predicated instructions.  The
instruction count is used in places to determine how many instructions to
copy, predicate, etc. and things get confused if that count includes the
extra cost for microcoded ops.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117332 91177308-0d34-0410-b5e6-96231b3b80d8