Remove EnhancedBugReport and RangedBugReport - pull all the extra functionality they provided into their parent BugReport. The only functional changes are: made getRanges() non const - it adds default range to Ranges if none are supplied, made getStmt() private, which was another FIXME.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@137894 91177308-0d34-0410-b5e6-96231b3b80d8