revert r325515: [TTI CostModel] change default cost of FP ops to 1 (PR36280)

There are too many perf regressions resulting from this, so we need to 
investigate (and add tests for) targets like ARM and AArch64 before 
trying to reinstate.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@325658 91177308-0d34-0410-b5e6-96231b3b80d8
11 files changed