JVM_IR: generate non-null assertions for arguments

compiler/testData/codegen/box/builtinStubMethods/mapGetOrDefault/noTypeSafeBridge.kt

@@ -3,6 +3,10 @@
 // FULL_JDK
 // WITH_RUNTIME
 
+// Bridges are not generated because their signatures would conflict. The logic
+// should be inserted directly into existing methods, but this is not implemented.
+// IGNORE_BACKEND: JVM_IR
+
 class A : MutableMap<Any, Any?> {
     override val entries: MutableSet<MutableMap.MutableEntry<Any, Any?>>
         get() = throw UnsupportedOperationException()