[IR] Fix warnings (#143752)
This patch fixes:
llvm/lib/IR/DIBuilder.cpp:1072:18: error: unused function
'getDeclareIntrin' [-Werror,-Wunused-function]
llvm/include/llvm/IR/DIBuilder.h:51:15: error: private field
'DeclareFn' is not used [-Werror,-Wunused-private-field]
llvm/include/llvm/IR/DIBuilder.h:52:15: error: private field
'ValueFn' is not used [-Werror,-Wunused-private-field]
llvm/include/llvm/IR/DIBuilder.h:53:15: error: private field
'LabelFn' is not used [-Werror,-Wunused-private-field]
llvm/include/llvm/IR/DIBuilder.h:54:15: error: private field
'AssignFn' is not used [-Werror,-Wunused-private-field]
