Prefer similar line breaks.

This adds a penalty for clang-format for each break that occurs in
a set of parentheses (including fake parenthesis that determine
the range of certain operator precendences) that have not yet been
broken. Thereby, clang-format prefers similar line breaks.

This fixes llvm.org/PR15506.

Before:
const int kTrackingOptions =
    NSTrackingMouseMoved | NSTrackingMouseEnteredAndExited |
    NSTrackingActiveAlways;

After:
const int kTrackingOptions = NSTrackingMouseMoved |
                             NSTrackingMouseEnteredAndExited |
                             NSTrackingActiveAlways;

Also removed ParenState::ForFakeParenthesis which has become unused.

llvm-svn: 185822