clang-format: Slightly row back on r256343 by increasing penalty for

breaking between array subscripts.

Before:
  if (aaaaaaaaaaaaaaaaaaaaaaaa && aaaaaaaaaaaaaaaaaaa[aaaaaaaaaaaaa]
                                                     [aaaaaaaaaaaaa])
After:
  if (aaaaaaaaaaaaaaaaaaaaaaaa &&
      aaaaaaaaaaaaaaaaaaa[aaaaaaaaaaaaa][aaaaaaaaaaaaa])

llvm-svn: 256640