clang-format: [Java] Improve generic support.

Before:
  Iterable< ? > a;
  Iterable< ? extends SomeObject > a;

After:
  Iterable<?> a;
  Iterable<? extends SomeObject> a;

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@220281 91177308-0d34-0410-b5e6-96231b3b80d8