"Bin-packing" here means allowing multiple parameters on one line, if a
function call/declaration is spread over multiple lines.

This is required by the Chromium style guide and probably desired for
the Google style guide. Not making changes to LLVM style as I don't have
enough data.

With this enabled, we format stuff like:
aaaaaaaaaaaaaaa(aaaaaaaaaa,
                aaaaaaaaaa,
		aaaaaaaaaaaaaaaaaaaaaaa).aaaaaaaaaaaaaaaaaa();

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172617 91177308-0d34-0410-b5e6-96231b3b80d8