[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/classes/smartCastInValInitialization.sig.kt.txt

@@ -0,0 +1,46 @@
+// CHECK:
+//   Mangled name: MessageBusImpl
+//   Public signature: /MessageBusImpl|null[0]
+open class MessageBusImpl {
+  // CHECK:
+  //   Mangled name: MessageBusImpl{}parentBus
+  //   Public signature: /MessageBusImpl.parentBus|4372009635220349355[0]
+  val parentBus: Any?
+    // CHECK JVM_IR:
+    //   Mangled name: MessageBusImpl#<get-parentBus>(){}kotlin.Any?
+    //   Public signature: /MessageBusImpl.parentBus.<get-parentBus>|-5686140196600425134[0]
+    // CHECK JS_IR NATIVE:
+    //   Mangled name: MessageBusImpl#<get-parentBus>(){}
+    //   Public signature: /MessageBusImpl.parentBus.<get-parentBus>|-4473545730438591287[0]
+    get
+
+  // CHECK:
+  //   Mangled name: MessageBusImpl#<init>(){}
+  //   Public signature: /MessageBusImpl.<init>|-5645683436151566731[0]
+  constructor() /* primary */
+
+}
+
+// CHECK:
+//   Mangled name: RootBus
+//   Public signature: /RootBus|null[0]
+class RootBus : MessageBusImpl {
+  // CHECK:
+  //   Mangled name: RootBus#<init>(){}
+  //   Public signature: /RootBus.<init>|-5645683436151566731[0]
+  constructor() /* primary */
+
+  // CHECK:
+  //   Mangled name: RootBus{}parentBus
+  //   Public signature: /RootBus.parentBus|4372009635220349355[0]
+  /* fake */ override val parentBus: Any?
+    // CHECK JVM_IR:
+    //   Mangled name: RootBus#<get-parentBus>(){}kotlin.Any?
+    //   Public signature: /RootBus.parentBus.<get-parentBus>|-5686140196600425134[0]
+    // CHECK JS_IR NATIVE:
+    //   Mangled name: RootBus#<get-parentBus>(){}
+    //   Public signature: /RootBus.parentBus.<get-parentBus>|-4473545730438591287[0]
+    /* fake */ override get(): Any?
+
+}
+