The assert was firing off when there were already
MAX_DESCRIPTOR_SET_COMBINED_BUFFERS_DYNAMIC dynamic descriptors
(which is valid), while the last set layouts contained no
dynamic descriptors, because the offset was already set to
MAX_DESCRIPTOR_SET_COMBINED_BUFFERS_DYNAMIC, which shouldn't
matter if there are no dynamic descriptors left.

Bug b/118386749 b/123244275

Change-Id: I1536e6a47b7837c6b052d4e169a5396daf7d34cb
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/34148Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>