When emit NoOp bitcast for GEP Ptr Operand, should use SourceElementType
instead of ResultElementType.
**Behavior Before Change**
Redundant bitcast like
` bitcast ptr addrspace(3) @gs to ptr addrspace(3)`
will be generated for llvm/test/CodeGen/DirectX/typed_ptr.ll
**Behavior After Change**
No bitcast will be generated.
Fixes https://github.com/llvm/llvm-project/issues/65183