[ORC] Return ExecutorAddrs rather than JITEvaluatedSymbols from LLJIT::lookup.Clients don't care about linkage, and ExecutorAddr is much more ergonomic.
Cleanup includes: LLVMTargetMost notably, Pass.h is no longer included by TargetMachine.hbefore: 1063570306after: 1063332844Differential Revision: https://reviews.llvm.org/D121168
[ORC][examples] Add missing library dependencies.
[ORC][examples] Add an OrcV2 example for IR optimization via IRTransformLayer.Shows how to write a custom IR transform to apply a legacy::PassManagerpipeline.