[llvm] [offload][OpenMP] Fix record replay when no memory is used (PR #201771)

[Robert Imschweiler via llvm-commits]

================

----------------
ro-i wrote:

at this point, DeviceMemory holds `DeviceMemoryMB.get()->getBufferStart()`. But DeviceMemoryMB is a unique_ptr in the scope of the `if (RecordSize) {`, which means that it's freed here?

https://github.com/llvm/llvm-project/pull/201771