[NFC][ScopBuilder] Move addUserContext to ScopBuilder

Scope of changes:
1) Moved addUserContext to ScopBuilder.
2) Moved command line option UserContextStr to ScopBuilder.

Differential Revision: https://reviews.llvm.org/D63740

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@366266 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed