Adding an assert to help catch possible buffer underruns.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195024 91177308-0d34-0410-b5e6-96231b3b80d8
Remove clang man page reference to --analyze, and point people to the analyzer website.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195027 91177308-0d34-0410-b5e6-96231b3b80d8