Revert "Nested transactions share the parent's llvm::Module."
Revert "Nested transactions share the parent's llvm::Module."

This reverts commit 9ae79df05006247cfed1e7e89e0fd371f3eba459.

karies/cling,marsupial/cling,perovic/cling,karies/cling,karies/cling,marsupial/cling,root-mirror/cling,perovic/cling,marsupial/cling,perovic/cling,karies/cling,marsupial/cling,root-mirror/cling,perovic/cling,root-mirror/cling,root-mirror/cling,perovic/cling,karies/cling,root-mirror/cling,root-mirror/cling,marsupial/cling,karies/cling,marsupial/cling