clang-format: Fix binary operator detection before lambdas.

Before:
  bool foo = true&& [] { return false; }();

After:
  bool foo = true && [] { return false; }();

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@208288 91177308-0d34-0410-b5e6-96231b3b80d8