[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/delegatedImplementationWithExplicitOverride.sig.kt.txt

@@ -0,0 +1,62 @@
+// CHECK:
+//   Mangled name: C
+//   Public signature: /C|null[0]
+class C : IFooBar {
+  // CHECK:
+  //   Mangled name: C#<init>(){}
+  //   Public signature: /C.<init>|-5645683436151566731[0]
+  constructor() /* primary */
+  // CHECK:
+  //   Mangled name: C.$$delegate_0
+  //   Public signature: /C.$$delegate_0|-7286425919675154353[0]
+  private /* final field */ val $$delegate_0: FooBarImpl
+  // CHECK:
+  //   Mangled name: C#foo(){}
+  //   Public signature: /C.foo|-1041209573719867811[0]
+  override fun foo(): Unit
+
+  // CHECK:
+  //   Mangled name: C#bar(){}
+  //   Public signature: /C.bar|496682602797471549[0]
+  override fun bar(): Unit
+
+}
+
+// CHECK:
+//   Mangled name: IFooBar
+//   Public signature: /IFooBar|null[0]
+interface IFooBar {
+
+  // CHECK:
+  //   Mangled name: IFooBar#bar(){}
+  //   Public signature: /IFooBar.bar|496682602797471549[0]
+  abstract fun bar(): Unit
+
+  // CHECK:
+  //   Mangled name: IFooBar#foo(){}
+  //   Public signature: /IFooBar.foo|-1041209573719867811[0]
+  abstract fun foo(): Unit
+
+}
+
+// CHECK:
+//   Mangled name: FooBarImpl
+//   Public signature: /FooBarImpl|null[0]
+object FooBarImpl : IFooBar {
+  // CHECK:
+  //   Mangled name: FooBarImpl#<init>(){}
+  //   Public signature: /FooBarImpl.<init>|-5645683436151566731[0]
+  private constructor() /* primary */
+
+  // CHECK:
+  //   Mangled name: FooBarImpl#bar(){}
+  //   Public signature: /FooBarImpl.bar|496682602797471549[0]
+  override fun bar(): Unit
+
+  // CHECK:
+  //   Mangled name: FooBarImpl#foo(){}
+  //   Public signature: /FooBarImpl.foo|-1041209573719867811[0]
+  override fun foo(): Unit
+
+}
+