Generate type-safe barrier in method body

In cases when signature of special bridge is the same as current method,
but type is not 'Any?'.

Also there is tiny optimization:
only null check needed if value parameter type is mapped to Object,
but it's not nullable.

 #KT-9973 Fixed

compiler/testData/codegen/box/specialBuiltins/notEmptyMap.kt

@@ -0,0 +1,32 @@
+private object NotEmptyMap : MutableMap<Any, Any> {
+    override fun containsKey(key: Any): Boolean = true
+    override fun containsValue(value: Any): Boolean = true
+    override fun get(key: Any): Any? = Any()
+    override fun remove(key: Any): Any? = Any()
+
+    override val size: Int get() = 0
+    override fun isEmpty(): Boolean = true
+    override fun put(key: Any, value: Any): Any? = throw UnsupportedOperationException()
+    override fun putAll(from: Map<out Any, Any>): Unit = throw UnsupportedOperationException()
+    override fun clear(): Unit = throw UnsupportedOperationException()
+    override val entries: MutableSet<MutableMap.MutableEntry<Any, Any>> get() = null!!
+    override val keys: MutableSet<Any> get() = null!!
+    override val values: MutableCollection<Any> get() = null!!
+}
+
+
+fun box(): String {
+    val n = NotEmptyMap as MutableMap<Any?, Any?>
+
+    if (n.get(null) != null) return "fail 1"
+    if (n.containsKey(null)) return "fail 2"
+    if (n.containsValue(null)) return "fail 3"
+    if (n.remove(null) != null) return "fail 4"
+
+    if (n.get("") == null) return "fail 5"
+    if (!n.containsKey("")) return "fail 6"
+    if (!n.containsValue("")) return "fail 7"
+    if (n.remove("") == null) return "fail 8"
+
+    return "OK"
+}