stage1: fix constness in some corner cases

- for one-possible-value types, ir_analyze_struct_field_ptr()
  no longer hardcodes const/volatile

- when slicing arrays, ir_analyze_instruction_slice()
  no longer consults ConstValSpecialStatic

closes #5474
c0c9d11d8cMichael Dusan committed on 6/5/2020, 4:49:57 AMparentf839d34
3 files changedLine totals unavailable