message: Add `i16` and `u16` primitive layout.
diff: @@ -178,9 +178,11 @@ pub struct AllocExtra {
  pub struct PrimitiveLayouts<'tcx> {
  pub unit: TyAndLayout<'tcx>,
  pub i8: TyAndLayout<'tcx>,
  + pub i16: TyAndLayout<'tcx>,
  pub i32: TyAndLayout<'tcx>,
  pub isize: TyAndLayout<'tcx>,
  pub u8: TyAndLayout<'tcx>,
  + pub u16: TyAndLayout<'tcx>,
  pub u32: TyAndLayout<'tcx>,
  pub usize: TyAndLayout<'tcx>,
  pub bool: TyAndLayout<'tcx>,
  @@ -194,9 +196,11 @@ impl<'mir, 'tcx: 'mir> PrimitiveLayouts<'tcx> {
  Ok(Self {
  unit: layout_cx.layout_of(tcx.mk_unit())?,
  i8: layout_cx.layout_of(tcx.types.i8)?,
  + i16: layout_cx.layout_of(tcx.types.i16)?,
  i32: layout_cx.layout_of(tcx.types.i32)?,
  isize: layout_cx.layout_of(tcx.types.isize)?,
  u8: layout_cx.layout_of(tcx.types.u8)?,
  + u16: layout_cx.layout_of(tcx.types.u16)?,
  u32: layout_cx.layout_of(tcx.types.u32)?,
  usize: layout_cx.layout_of(tcx.types.usize)?,
  bool: layout_cx.layout_of(tcx.types.bool)?,
  