[llvm] [memprof] Use std::move in toMemProfRecord (PR #93133)

[Snehasish Kumar via llvm-commits]

https://github.com/snehasish commented:

This leaves the current IndexedMemProfRecord in a bad state. How can we ensure that users don't accidentally try to read after this method has been called?

I'm also skeptical how much impact this has in real usage since we don't expect to read all records for a single module. Perhaps we can try safer optimizations such as reserve() for the AllocSites vector (and the Callsites vector too)?

https://github.com/llvm/llvm-project/pull/93133