[mlir]Moves the StateStack to IR folder from Support folder. (#145598)

[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.

utils/bazel/llvm-project-overlay/mlir/BUILD.bazel

@@ -4845,11 +4845,7 @@ cc_library(
     ]),
     hdrs = glob(["include/mlir/Support/*.h"]),
     includes = ["include"],
-    deps = [
-        "//llvm:Support",
-        "//mlir:IR",
-    ],
-)
+    deps = ["//llvm:Support"],)
 
 cc_library(
     name = "Debug",