[test] Get rid of SKIP_SIGNATURE_DUMP directive in irText tests

Sometimes there are legitimate reasons to have two separate signature
dumps for K1 and K2.

^KT-61797 Fixed

compiler/testData/ir/irText/classes/delegatedGenericImplementation.kt

@@ -1,6 +1,3 @@
-// SKIP_SIGNATURE_DUMP
-// ^ K1 generates a useless delegate field for the Test2 class, K2 does not
-
 interface IBase<A> {
     fun <B> foo(a: A, b: B)
     val <C> C.id: Map<A, C>?