[LLVM] The output of WarnMissedTransformationsPass seems not controllable

The output of WarnMissedTransformationsPass seems not able to be controlled by ` -pass-remarks-missed` and `-pass-remarks-analysis`. In `llvm/test/Transforms/LoopTransformWarning/unrolling-remarks-missed.ll`, the test still passes after I removed ` -pass-remarks-missed` and `-pass-remarks-analysis`. It looks inconsistent with the original design intention.

The practical affect of this is, now users may suffers from the a lot of warning but they can't do anything about it if they can't modify the source code (image the source code comes from third party libraries.)

Start with llvm/test/Transforms/LoopTransformWarning/unrolling-remarks-missed.ll and inspect how WarnMissedTransformationsPass handles -pass-remarks-missed and -pass-remarks-analysis. Compare the test output with and without those options. Done means the pass output follows the remark flags and the test covers that behavior.

Written by the indexing model from the issue text.