[K2, MPP] Restore ir functions actualization by argument types instead of full signatures

Refactor IrActualizer

compiler/testData/diagnostics/tests/multiplatform/enum/javaEnum.fir.kt

@@ -2,7 +2,7 @@
 // FILE: common.kt
 
 <!NO_ACTUAL_FOR_EXPECT{JVM}!>expect enum class Foo {
-    <!NO_ACTUAL_FOR_EXPECT{JVM}!>ENTRY<!>
+    ENTRY
 }<!>
 
 expect enum class _TimeUnit

compiler/testData/diagnostics/tests/multiplatform/java/flexibleTypes.fir.kt

@@ -8,7 +8,7 @@ expect class Foo {
 
     <!NO_ACTUAL_FOR_EXPECT{JVM}!>fun f2(s: List<String>?): MutableMap<Boolean?, Foo><!>
 
-    <!NO_ACTUAL_FOR_EXPECT{JVM}!>fun <T : Set<Number>> f3(t: T): T?<!>
+    fun <T : Set<Number>> f3(t: T): T?
 }
 
 // MODULE: m2-jvm()()(m1-common)