[OM] Use Object Location in partially evaluated ObjectValue.

When we create partially evaluated ObjectValues, we should use the
Object's Location, rather than the location of the field being
evaluated.

integration_test/Bindings/Python/dialects/om.py

@@ -180,7 +180,7 @@
 for (name, field) in obj:
  # location from om.class.field @child, %0 : !om.class.type<@Child>
  # CHECK: name: child, field: <circt.dialects.om.Object object
- # CHECK-SAME: loc: loc("-":31:7)
+ # CHECK-SAME: loc: loc("-":30:12)
  # location from om.class.field @field, %param : !om.integer
  # CHECK: name: field, field: 42
  # CHECK-SAME: loc: loc("-":27:7)

lib/Dialect/OM/Evaluator/Evaluator.cpp

@@ -167,9 +167,12 @@ FailureOr<evaluator::EvaluatorValuePtr> circt::om::Evaluator::getOrCreateValue(
  evaluator::PathValue::getEmptyPath(loc));
  return success(result);
  })
- .Case<ListCreateOp, TupleCreateOp, MapCreateOp, ObjectFieldOp,
- ObjectOp>([&](auto op) {
- return getPartiallyEvaluatedValue(op.getType(), loc);
+ .Case<ListCreateOp, TupleCreateOp, MapCreateOp, ObjectFieldOp>(
+ [&](auto op) {
+ return getPartiallyEvaluatedValue(op.getType(), loc);
+ })
+ .Case<ObjectOp>([&](auto op) {
+ return getPartiallyEvaluatedValue(op.getType(), op.getLoc());
  })
  .Default([&](Operation *op) {
  auto error = op->emitError("unable to evaluate value");