Purged unnecessary data structures from the IR
interpreter.  They are a legacy from when the IR
interpreter didn't work with materialized values
but rather got values directly from
ClangExpressionDeclMap.

Also updated the #includes for IRInterpreter
accordingly.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@180565 91177308-0d34-0410-b5e6-96231b3b80d8