[clang-format] Fix regression that breaks comments without a comment prefix
Summary:
Consider formatting the following code fragment with column limit 20:
```
{
// line 1
// line 2\
// long long long line
}
```
Before this fix the output is:
```
{
// line 1
// line 2\
// long long
long line
}
```
This patch fixes a regression that breaks the last comment line without
adding the '//' prefix.
Reviewers: djasper
Reviewed By: djasper
Subscribers: cfe-commits, klimek
Differential Revision: https://reviews.llvm.org/D29298
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@293548 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed
