Summary:
This commit fixes a regression introduced in r316095, where we don't match
inverted character classes when there's no negated characrers in the []'s.
rdar://problem/43060054
Reviewers: mclow.lists, timshen, EricWF
Subscribers: christof, dexonsmith, cfe-commits
Differential Revision: https://reviews.llvm.org/D50534
llvm-svn: 340609