[clang] [clang][Interp] Implement dynamic memory allocation handling (PR #70306)

[David Spickett via cfe-commits]

DavidSpickett wrote:

I know there is UB in there (https://github.com/llvm/llvm-project/issues/94741) so this is not unsurprising. Though so far none of that has been the cause of failures natively.

Let's see what Leandro finds.

https://github.com/llvm/llvm-project/pull/70306