group_ballot predicate argument should be defaulted

[Pennycook]

Describe the bug
sycl_ext_sub_group_mask defines ballot with predicate=true, but the implementation does not default the argument:

group_ballot

llvm/sycl/include/sycl/ext/oneapi/sub_group_mask.hpp

Line 270 in b13561c

group_ballot(Group g, bool predicate) {

To Reproduce

#include <sycl/sycl.hpp>

int main() {
  sycl::queue Q;
  Q.parallel_for(sycl::nd_range<1>{32, 32}, [=](sycl::nd_item<1> item) {
    auto Mask = sycl::ext::oneapi::group_ballot(item.get_sub_group());
  });
}

Environment (please complete the following information):

• OS: Linux, Windows
• Target device and vendor: Any
• DPC++ version: b13561c
• Dependencies version: N/A

Additional context
None.

[haroon26]

Hello @Pennycook! I am interested in compilers and looking to start contributing in them. Can you please assign this issue to me?