Fix FieldIndex issue and re-enable it in reflection.
diff --git a/slang_rs_reflection.h b/slang_rs_reflection.h
index deae276..bc5a71a 100644
--- a/slang_rs_reflection.h
+++ b/slang_rs_reflection.h
@@ -88,6 +88,8 @@
           mLicenseNote(ApacheLicenseNote),
           mUseStdout(UseStdout) {
       clear();
+      resetFieldIndex();
+      clearFieldIndexMap();
       return;
     }