remove !LBR constraints from merge passes

we have either converted candidates to castles already or we have converted them
back in the hope of merging them with other holders

src/nfagraph/ng_lbr.cpp

@@ -346,24 +346,4 @@ bytecode_ptr<NFA> constructLBR(const NGHolder &g,
     return constructLBR(proto, triggers, cc, rm);
 }
 
-/** \brief True if graph \p g could be turned into an LBR engine. */
-bool isLBR(const NGHolder &g, const Grey &grey) {
-    if (!grey.allowLbr) {
-        return false;
-    }
-
-    PureRepeat repeat;
-    if (!isPureRepeat(g, repeat)) {
-        DEBUG_PRINTF("not pure bounded repeat\n");
-        return false;
-    }
-
-    if (repeat.reports.size() != 1) {
-        DEBUG_PRINTF("too many reports\n");
-        return false;
-    }
-
-    return true;
-}
-
 } // namespace ue2

src/nfagraph/ng_lbr.h

@@ -66,9 +66,6 @@ constructLBR(const CastleProto &proto,
              const std::vector<std::vector<CharReach>> &triggers,
              const CompileContext &cc, const ReportManager &rm);
 
-/** \brief True if graph \p g could be turned into an LBR engine. */
-bool isLBR(const NGHolder &g, const Grey &grey);
-
 } // namespace ue2
 
 #endif // NG_LBR_H