stage2: improve handling of 0 bit types

* Sema: zirAtomicLoad handles 0-bit types correctly
 * LLVM backend: when lowering function types, elide parameters
   with 0-bit types.
 * Type: abiSize handles u0/i0 correctly
abc30f7948Andrew Kelley committed on 9/20/2021, 11:48:42 PMparent4b2d7a9
6 files changedLine totals unavailable