clang-format: [ObjC] Fix spacing in block variable parameters.

Before:
  { void (^block)(Object * x); }

After:
  { void (^block)(Object *x); }

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@220270 91177308-0d34-0410-b5e6-96231b3b80d8