[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/lambdas/anonymousFunction.sig.kt.txt

@@ -0,0 +1,18 @@
+// CHECK:
+//   Mangled name: {}anonymous
+//   Public signature: /anonymous|-1633601112294415930[0]
+val anonymous: Function0<Unit>
+  field
+    // CHECK JVM_IR:
+    //   Mangled name (compatible mode: false): {}anonymous#<no name provided>#static(){}
+    //   Mangled name (compatible mode: true):  anonymous#<no name provided>#static(){}
+    // CHECK JS_IR NATIVE:
+    //   Mangled name: #<get-anonymous>(){}
+    //   Public signature: /anonymous.<get-anonymous>|-7938030596525369571[0]
+    local fun <no name provided>(): Unit
+
+  // CHECK:
+  //   Mangled name: #<get-anonymous>(){}kotlin.Function0<kotlin.Unit>
+  //   Public signature: /anonymous.<get-anonymous>|4047260013555274752[0]
+  get
+