[IR][tests] Extend test for IR linkage issues related to functions

compiler/testData/klibABI/removeFunction/lib1/l1.kt

@@ -1,5 +1,7 @@
-
-
 fun foo(): String = "FAIL1"
+fun exp_foo(): String = "FAIL2"
 
-fun exp_foo() = "FAIL2"
+class A {
+    fun foo(): String = "FAIL3"
+    fun exp_foo(): String = "FAIL4"
+}

compiler/testData/klibABI/removeFunction/lib1/l1.kt.1

@@ -1,3 +1,5 @@
+fun foo(): String = "OK"
 
-
-fun foo(): String = "K"
+class A {
+    fun foo(): String = "OK"
+}