[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/variableAsFunctionCall.sig.kt.txt

@@ -0,0 +1,34 @@
+// CHECK JVM_IR:
+//   Mangled name: #k@kotlin.String(){}kotlin.Function0<kotlin.String>
+//   Public signature: /k|-4623891636485044145[0]
+// CHECK JS_IR NATIVE:
+//   Mangled name: #k@kotlin.String(){}
+//   Public signature: /k|603037284564559001[0]
+fun String.k(): Function0<String>
+
+// CHECK:
+//   Mangled name: #test1(kotlin.Function0<kotlin.Unit>){}
+//   Public signature: /test1|-2870537507416699845[0]
+fun test1(f: Function0<Unit>): Unit
+
+// CHECK:
+//   Mangled name: #test2(kotlin.Function1<kotlin.String,kotlin.Unit>){}
+//   Public signature: /test2|4596316013814715028[0]
+fun test2(f: @ExtensionFunctionType Function1<String, Unit>): Unit
+
+// CHECK JVM_IR:
+//   Mangled name: #test3(){}kotlin.String
+//   Public signature: /test3|3344305992477585251[0]
+// CHECK JS_IR NATIVE:
+//   Mangled name: #test3(){}
+//   Public signature: /test3|-3759735065270951803[0]
+fun test3(): String
+
+// CHECK JVM_IR:
+//   Mangled name: #test4(kotlin.String?){}kotlin.String?
+//   Public signature: /test4|-1434334118883225411[0]
+// CHECK JS_IR NATIVE:
+//   Mangled name: #test4(kotlin.String?){}
+//   Public signature: /test4|-2246924836724040051[0]
+fun test4(ns: String?): String?
+