Temporarily Revert "[CostModel] remove cost-kind predicate for intrinsics in...

Temporarily Revert "[CostModel] remove cost-kind predicate for intrinsics in basic TTI implementation"
as it's causing crashes in the optimizer. A reduced testcase has been posted as a follow-up.

This reverts commit f7eac51b.

Temporarily Revert "[CostModel] make default size cost for libcalls small (again)" as it depends upon the primary revert.

This reverts commit 8ec7ea3d.

Temporarily Revert "[CostModel] add tests for math library calls; NFC" as it depends upon the primary revert.

This reverts commit df09f825.

Temporarily Revert "[LoopUnroll] add test for full unroll that is sensitive to cost-model; NFC" as it depends upon the primary revert.

This reverts commit 618d555e.