[clang] Revert "[Clang] Fix missed initializer instantiation bug for variable templates" (PR #140930)

[Younan Zhang via cfe-commits]

https://github.com/zyn0217 approved this pull request.

I'll approve it, because I have a similar experience that swapping the deferred instantiation and immediate instantiation order caused a very subtle failure of return type deduction.

However, just as what @AaronBallman suggested, please hold off landing for some time to see if a reduced example could help us pinpoint the underlying issue.

https://github.com/llvm/llvm-project/pull/140930