Don't put spaces around ##.

In Clang/LLVM this seems to be the more common formatting for ##s. There
might still be case that we miss, but we'll fix those as we go along.

Before:

  #define A(X)
    void function ## X();

After:

  #define A(X)
    void function##X();

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171862 91177308-0d34-0410-b5e6-96231b3b80d8