Stronger respect the input codes line breaks wrt. comments.

clang-format should not change whether or not there is a line break
before a line comment as this strongly influences the percieved binding.

User input: void f(int a,
                   // b is awesome
		   int b);
            void g(int a, // a is awesome
		   int b);
Before:     void f(int a, // b is awesome
                   int b);
            void g(int a, // a is awesome
		   int b);
After:      <unchanged from input>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172361 91177308-0d34-0410-b5e6-96231b3b80d8