[bazel] Add rules for d3d12allocator This is a dependency of our Direct3D backend (which we want enable with viewer). Bug: b/256860862 Change-Id: I46a947c29042eb0cf6c307a810f25ce148c982c7 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1293537 Reviewed-by: Eric Boren <borenet@google.com>