clang-format: Increase the penalty for breaking between array subscripts.

Before:
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa[aaaaaaaaaaaaaaaaaaaaaaa]
                                    [a].aaaaaaaaaaaaaaaaaaaaaa();

After:
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa[aaaaaaaaaaaaaaaaaaaaaaa][a]
      .aaaaaaaaaaaaaaaaaaaaaa();

llvm-svn: 262292