[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/extensionPropertyGetterCall.sig.kt.txt

@@ -0,0 +1,20 @@
+// CHECK JVM_IR:
+//   Mangled name: #test5@kotlin.String(){}kotlin.String
+//   Public signature: /test5|7396849134865790053[0]
+// CHECK JS_IR NATIVE:
+//   Mangled name: #test5@kotlin.String(){}
+//   Public signature: /test5|6764932899271361379[0]
+fun String.test5(): String
+
+// CHECK:
+//   Mangled name: @kotlin.String{}okext
+//   Public signature: /okext|-7546376167507800782[0]
+val String.okext: String
+  // CHECK JVM_IR:
+  //   Mangled name: #<get-okext>@kotlin.String(){}kotlin.String
+  //   Public signature: /okext.<get-okext>|-4397362169527603922[0]
+  // CHECK JS_IR NATIVE:
+  //   Mangled name: #<get-okext>@kotlin.String(){}
+  //   Public signature: /okext.<get-okext>|-5103161093403962760[0]
+  get(): String
+