Fix multiline comment warning.

../unittests/Analysis/LazyCallGraphTest.cpp:45:1: warning: multi-line comment [-Wcomment]
 //        /  \
 ^


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207629 91177308-0d34-0410-b5e6-96231b3b80d8