[llvm] [CodeGen] Add MOTargetFlag4 to MachineMemOperand Flags (PR #120136)

[Jay Foad via llvm-commits]

https://github.com/jayfoad commented:

Adding another target flag seems uncontroversial. Does the MIR parsing code need to be updated as well as the printer?

https://github.com/llvm/llvm-project/pull/120136