When using information from dereferenceable assumptions, we need to make
sure that the memory is not freed between the assume and the specified
context instruction. Instead of just checking canBeFreed, check if there
any calls that may free between the assume and the context instruction.
This patch introduces a willNotFreeBetween to check for calls that may
free between an assume and a context instructions, to also be used in
https://github.com/llvm/llvm-project/pull/161255.
PR: https://github.com/llvm/llvm-project/pull/161725