Integrate LLVM at 1506ba95d7c3dca1abff0190550945f6cc263a99 (#4230)

Update LLVM to
llvm/llvm-project@1506ba9.

---------

Signed-off-by: Vivek Khandelwal <vivekkhandelwal1424@gmail.com>
Co-authored-by: https://github.com/penguin-wwy

Author: vivekkhandelwal1

CMakeLists.txt

@@ -253,6 +253,8 @@ endif()
 if (TORCH_MLIR_ENABLE_STABLEHLO AND NOT TORCH_MLIR_USE_EXTERNAL_STABLEHLO)
   set(STABLEHLO_BUILD_EMBEDDED ON)
   set(STABLEHLO_ENABLE_BINDINGS_PYTHON ON)
+  message(STATUS "Using LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING in: ${LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING}")
+  set(LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING "DISABLED")
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/externals/stablehlo
     ${CMAKE_CURRENT_BINARY_DIR}/stablehlo
     EXCLUDE_FROM_ALL)