clang-format: Be slightly more aggressive on single-line functions.

So that JS functions can also be merged into a single line.

Before:
  var func = function() {
    return 1;
  };

After:
  var func = function() { return 1; };

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@208176 91177308-0d34-0410-b5e6-96231b3b80d8