[clang] [clang-repl] fix top-level statement declaration context (PR #75547)

[Pavel Kalugin via cfe-commits]

p4vook wrote:

Looking for someone with knowledge of Clang AST, because I can't figure out the correct context to insert the statement into. Current implementation breaks "for" loop.

https://github.com/llvm/llvm-project/pull/75547