[analyzer] Add -analyzer-purge option which can take on multiple values, remove -analyzer-purge=none. (Small refactor as well: move the work of constructing AnalysisManager from the callers to the class itself.)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140838 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed