[llvm] [RuntimeDyld][Windows] Allocate space for dllimport things. (PR #102586)

[Alastair Houghton via llvm-commits]

al45tair wrote:

This is a cherry pick of https://github.com/swiftlang/llvm-project/pull/9071.

https://github.com/llvm/llvm-project/pull/102586