Revert "[lldb][Test][NFC] TestExternalCtorDtorLookup: add more instantiations...

Revert "[lldb][Test][NFC] TestExternalCtorDtorLookup: add more instantiations to test linkage name is correct"

This reverts commit 3c160d30.

This patch depends on the reverted patch in https://reviews.llvm.org/D143652

Differential Revision: https://reviews.llvm.org/D143652