JVM IR: do not generate certain special bridges as final

Special bridges which are generated as a replacement for a non-final
fake override and use invokespecial to call the already existing
implementation in the superclass, should not be final. Otherwise we
can't generate an override for the original Kotlin function in a
subclass with the same JVM signature.

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

@@ -0,0 +1,17 @@
+// TARGET_BACKEND: JVM
+// IGNORE_BACKEND_FIR: JVM_IR
+
+import java.util.AbstractMap
+
+// Neither of getSize, getKeys, getEntries, getValues generated here should be final.
+abstract class AbstractMutableMap<K, V> : MutableMap<K, V>, AbstractMap<K, V>()
+
+class MyMap<K, V> : AbstractMutableMap<K, V>() {
+    override val size: Int
+        get() = 1
+    override val entries: MutableSet<MutableMap.MutableEntry<K, V>>
+        get() = null!!
+}
+
+fun box(): String =
+    if (MyMap<String, String>().size == 1) "OK" else "Fail"