[IR] Dump IdSignatures and mangled names in irText tests

The reason #1 for this feature is that we want to test IdSignatures
generated for declarations. Currently, there is no (easy) way to ensure
that a change in the signature building logic doesn't cause any breaking
changes wrt klibs.

Now, most IdSignatures include hashed mangled names in them, so even if
we catch a regression where the included hash changes, there would be no
way of knowing immediately what caused it, unless we'd also have mangled
names in the expectations.

The reason #2 is to test the manglers themselves. Currently, there are
no tests for them. They heavily duplicate each other, this is already
causing issues (see KT-57427) that would be very hard to catch without
these tests.

^KT-58238 Fixed

compiler/testData/ir/irText/expressions/implicitNotNullInDestructuringAssignment.sig.kt.txt

@@ -0,0 +1,15 @@
+// CHECK JVM_IR:
+//   Mangled name: #component1@J?(){}kotlin.Int
+//   Public signature: /component1|-3884047873137386118[0]
+operator fun J?.component1(): Int
+
+// CHECK JVM_IR:
+//   Mangled name: #component2@J(){}kotlin.Int
+//   Public signature: [ File 'implicitNotNullInDestructuringAssignment.kt' <- /component2|-623550756830644944[0] ]
+private operator fun J.component2(): Int
+
+// CHECK:
+//   Mangled name: #test(){}
+//   Public signature: /test|6620506149988718649[0]
+fun test(): Unit
+