JVM: write back to tailrec function parameters if possible

This makes the debugger update the values when entering a recursive
call, and also uses fewer variable slots.

This may also work on the JS backend, but Native would probably require
something else.

^KT-47203 Fixed

compiler/ir/backend.jvm/entrypoint/src/org/jetbrains/kotlin/backend/jvm/JvmGeneratorExtensionsImpl.kt

@@ -249,4 +249,7 @@ open class JvmGeneratorExtensionsImpl(
         }
         return null
     }
+
+    override val parametersAreAssignable: Boolean
+        get() = true
 }