[MLIR] Fix circular dependency introduced in In
https://github.com/llvm/llvm-project/pull/144897. This PR is to break
the dependency. by moving StateStack to IR folder
This commit resolves a circular dependency issue between mlir/Support
and mlir/IR:
- Move StateStack.h and StateStack.cpp from Support to IR folder
- Update CMakeLists.txt files to reflect the new locations
- Update Bazel BUILD file to maintain correct dependencies
- Update includes in affected files (flang, Target/LLVMIR)
The circular dependency was caused by StateStack.h depending on
IR/Visitors.h
while other IR files depended on Support. Moving StateStack to IR
eliminates
this cycle while maintaining proper separation of concerns.
