[modules] Improve error messages.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 27105dafe7c843d857af2a4e5f3a5b889874486b..565b31e018377e9eabfa56b3e5a345ae8354e3ad 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -8048,6 +8048,14 @@ Object* ModuleInfoEntry::module_request() const {
   return get(kModuleRequestIndex);
 }
 
+int ModuleInfoEntry::beg_pos() const {
+  return Smi::cast(get(kBegPosIndex))->value();
+}
+
+int ModuleInfoEntry::end_pos() const {
+  return Smi::cast(get(kEndPosIndex))->value();
+}
+
 FixedArray* ModuleInfo::module_requests() const {
   return FixedArray::cast(get(kModuleRequestsIndex));
 }