Auto merge of #116482 - matthewjasper:thir-unsafeck-inline-constants, r=b-naber

Fix inline const pattern unsafety checking in THIR

Fix THIR unsafety checking of inline constants.
- Steal THIR in THIR unsafety checking (if enabled) instead of MIR lowering.
- Represent inline constants in THIR patterns.

Author: bors