Remove reference to fixed issue in test data

These two tests are now failing with IR fake override builder because
e.g. the fake override `MyMutableList.foo` has two overridden symbols:
`MyList.foo` and `MyMutableCollection.foo`, as opposed to the normal K2
mode which only has the former.

This seems to only affect the printed IR dump. Note that in K1 there
were two overridden symbols as well.

compiler/testData/codegen/box/functions/delegatedPropertyWithMultipleOverriddens_generics.kt

@@ -1,6 +1,7 @@
 // ISSUE: KT-55828
 // DUMP_IR
-// IGNORE_CODEGEN_WITH_IR_FAKE_OVERRIDE_GENERATION: KT-61386
+// IGNORE_CODEGEN_WITH_IR_FAKE_OVERRIDE_GENERATION: extra overridden symbols for declarations in MyMutableList.
+//   ^ This is most likely not a problem, and IR dump can be changed once IR fake override generation is enabled by default.
 
 interface MyCollection<out E1> {
     fun foo(): E1

compiler/testData/codegen/box/functions/delegatedPropertyWithMultipleOverriddens_noGenerics.kt

@@ -1,6 +1,7 @@
 // ISSUE: KT-55828
 // DUMP_IR
-// IGNORE_CODEGEN_WITH_IR_FAKE_OVERRIDE_GENERATION: KT-61386
+// IGNORE_CODEGEN_WITH_IR_FAKE_OVERRIDE_GENERATION: extra overridden symbols for declarations in MyMutableList.
+//   ^ This is most likely not a problem, and IR dump can be changed once IR fake override generation is enabled by default.
 
 interface MyCollection {
     fun foo(): String