Provide an InstId when evaluating a constant in cases where one is needed (#5202)

For each kind of instruction, specify whether its constant evaluation
needs an `InstId` or not. If it does, ensure that all constant
evaluation of that instruction provides one. Otherwise, allow calling
into the evaluator without providing an `InstId`.

This allows us to reliably use the `InstId` in evaluation steps that
either need a location or need to look at the original operands of the
instruction prior to evaluation, and also to support `TryEvalInst` calls
safely for instructions whose evaluation does not need an `InstId`.

toolchain/check/interface.cpp

@@ -91,11 +91,10 @@ static auto GetSelfFacet(Context& context,
   auto type_inst_id = context.types().GetInstId(self_type_id);
   auto witnesses_block_id =
       context.inst_blocks().AddCanonical({self_witness_id});
-  auto self_value_const_id =
-      TryEvalInst(context, SemIR::InstId::None,
-                  SemIR::FacetValue{.type_id = self_facet_type_id,
-                                    .type_inst_id = type_inst_id,
-                                    .witnesses_block_id = witnesses_block_id});
+  auto self_value_const_id = TryEvalInst(
+      context, SemIR::FacetValue{.type_id = self_facet_type_id,
+                                 .type_inst_id = type_inst_id,
+                                 .witnesses_block_id = witnesses_block_id});
   return context.constant_values().GetInstId(self_value_const_id);
 }
 
@@ -164,8 +163,8 @@ auto GetSelfSpecificForInterfaceMemberWithSelfType(
       CARBON_CHECK(entity_name.bind_index_value >= 0);
       bind_name.entity_name_id =
           context.entity_names().AddCanonical(entity_name);
-      new_arg_id = context.constant_values().GetInstId(
-          TryEvalInst(context, arg_id, bind_name));
+      new_arg_id =
+          context.constant_values().GetInstId(TryEvalInst(context, bind_name));
     }
     arg_ids.push_back(new_arg_id);
   }