[KLIB tool] Add tests for dumping IR signatures

^KT-62341

native/native.tests/testData/klib/dump-signatures/imported_declarations.ir-signatures.v2.txt

@@ -0,0 +1,15 @@
+// Declared signatures: 1
+imported/test|test(){}[0]
+
+// Imported signatures: 11
+bar/publicVal.<get-publicVal>|<get-publicVal>(){}[0]
+bar/publicVal|<get-publicVal>(){}[0]
+foo/PublicClass.<init>|<init>(kotlin.Int){}[0]
+foo/PublicClass|null[0]
+foo/publicFun|publicFun(){}[0]
+kotlin.collections/List|null[0]
+kotlin/Any|null[0]
+kotlin/CharSequence|null[0]
+kotlin/String|null[0]
+kotlin/Unit|null[0]
+kotlin/toString|toString@kotlin.Any?(){}[0]