shader: Add support for "negative" and unaligned offsets

"Negative" offsets don't exist. They are shown as such due to a bug in
nvdisasm.

Unaligned offsets have been proved to read the aligned offset. For
example, when reading an U32, if the offset is 6, the offset read will
be 4.

src/shader_recompiler/backend/glasm/emit_glasm_context_get_set.cpp

@@ -18,6 +18,14 @@ void GetCbuf(EmitContext& ctx, IR::Inst& inst, const IR::Value& binding, ScalarU
         throw NotImplementedException("Indirect constant buffer loading");
     }
     const Register ret{ctx.reg_alloc.Define(inst)};
+    if (offset.type == Type::U32) {
+        // Avoid reading arrays out of bounds, matching hardware's behavior
+        const u32 imm_offset{offset.imm_u32};
+        if (offset.imm_u32 >= 0x10'000) {
+            ctx.Add("MOV.S {},0;", ret);
+            return;
+        }
+    }
     ctx.Add("LDC.{} {},c{}[{}];", size, ret, binding.U32(), offset);
 }