Call method references search in UnusedSymbolInspection.hasReferences to fix secondary constructor search

Makes #KT-12500 Fixed
Makes #KT-12501 Fixed

idea/testData/quickfix/removeUnused/secondaryConstructorFromJava.before.Main.kt

@@ -0,0 +1,11 @@
+// "Safe delete constructor" "false"
+// ACTION: Convert to primary constructor
+// ACTION: Make internal
+// ACTION: Make private
+// ACTION: Make protected
+
+class Ctor {
+    <caret>constructor(p: Int)
+
+    fun justCompare() {}
+}