[BOLT][NFC] Warning for deprecated option '-reorder-blocks=cache+'

Emit warning when using deprecated option '-reorder-blocks=cache+'.
Auto switch to option '-reorder-blocks=ext-tsp'.

Test Plan:
```
ninja check-bolt
```
Added a new test cache+-deprecated.test.
Run and verify that the upstream tests are passed.

Reviewed By: rafauler, Amir, maksfb

Differential Revision: https://reviews.llvm.org/D126722