[llvm] [SandboxIR] Add extern templates for GlobalWithNodeAPI (PR #111940)

[via llvm-commits]

vporpo wrote:

I am trying to understand why these would need to be explicitly exported for SandboxIRTests. The tests don't use the template directly.

There are other similar CRTPs, like the `SingleLLVMInstructionImpl` in `llvm//SandboxIR/Instruction.h`, would they also need to be explicitly exported too? 

https://github.com/llvm/llvm-project/pull/111940