[llvm] [llvm][CodeGen] Reanalyze corrupted live intervals in window scheduling (PR #101945)

[Hua Tian via llvm-commits]

huaatian wrote:

This bug was reported in https://github.com/llvm/llvm-project/pull/99454.
The root cause of the issue is that slot index and live interval information are required when constructing TripleMBB. During the analysis of some virtual registers, references are made to an MBB that has already been processed by the machine pipeliner. Since the machine pipeliner does not preserve live interval and slot index information, the following error occurs:
![image](https://github.com/user-attachments/assets/5f240511-235d-44c3-8989-d21de25a9051)
The probability of this situation occurring is low. Typically, when updating the LiveIntervals in TripleMBB, scheduled MBBs are not referenced. Therefore, in such cases, we reanalyze the live intervals.
PS :This error scenario is difficult to reproduce, so we can only try to simplify the reported scenario as much as possible.

https://github.com/llvm/llvm-project/pull/101945