clang-format: Slightly weaken AlignAfterOpenBracket=AlwaysBreak.

If a call takes a single argument, using AlwaysBreak can lead to lots
of wasted lines and additional indentation without improving the
readability in a significant way.

Before:
  caaaaaaaaaaaall(
      caaaaaaaaaaaall(
          caaaaaaaaaaaall(
              caaaaaaaaaaaaaaaaaaaaaaall(aaaaaaaaaaaaaa, aaaaaaaaa))));

After:
  caaaaaaaaaaaall(caaaaaaaaaaaall(caaaaaaaaaaaall(
      caaaaaaaaaaaaaaaaaaaaaaall(aaaaaaaaaaaaaa, aaaaaaaaa))));

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@263709 91177308-0d34-0410-b5e6-96231b3b80d8