GH-857: fix redefining record types used to index tables

This change tracks all TableVals created at parse-time whose index
depends on a given RecordType.  Should that RecordType be redef'd, those
TableVals are immediately rebuilt such that they are valid to
subsequently use in either parse-time initializations or eventually in
any arbitrary run-time expression.

src/main.cc

@@ -650,6 +650,7 @@ int main(int argc, char** argv)
 	is_parsing = false;
 
 	RecordVal::DoneParsing();
+	TableVal::DoneParsing();
 
 	init_general_global_var();
 	init_net_var();