Rework this code so that it does not trigger a compiler warning. NFC

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@219964 91177308-0d34-0410-b5e6-96231b3b80d8
Only call RemovePersistentVariable on expr_result if that shared
pointer contains something.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@219966 91177308-0d34-0410-b5e6-96231b3b80d8
I see this test case crash - skip for now

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@219970 91177308-0d34-0410-b5e6-96231b3b80d8