JVM IR: remove obsolete -Xir-check-local-names

This flag was added a long time ago, at the time when we weren't sure if
we were going to keep the naming of local and anonymous classes
completely equal to the naming in the old backend. Now that we've
decided that we won't keep it equal and there are a lot of differences
already, it's not useful anymore.

compiler/config.jvm/src/org/jetbrains/kotlin/config/JvmAnalysisFlags.kt

@@ -27,9 +27,6 @@ object JvmAnalysisFlags {
     @JvmStatic
     val suppressMissingBuiltinsError by AnalysisFlag.Delegates.Boolean
 
-    @JvmStatic
-    val irCheckLocalNames by AnalysisFlag.Delegates.Boolean
-
     @JvmStatic
     val disableUltraLightClasses by AnalysisFlag.Delegates.Boolean