[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/suspendConversionWithFunInterfaces.sig.kt.txt

@@ -0,0 +1,48 @@
+// CHECK:
+//   Mangled name: SuspendRunnable
+//   Public signature: /SuspendRunnable|null[0]
+fun interface SuspendRunnable {
+
+  // CHECK:
+  //   Mangled name: SuspendRunnable#invoke(){}
+  //   Public signature: /SuspendRunnable.invoke|-4663091332620260873[0]
+  abstract suspend fun invoke(): Unit
+
+}
+
+// CHECK:
+//   Mangled name: #bar1(){}
+//   Public signature: /bar1|1669926808669747346[0]
+fun bar1(): Unit
+
+// CHECK JVM_IR:
+//   Mangled name: #bar2(kotlin.String){}kotlin.Int
+//   Public signature: /bar2|3267780493794663662[0]
+// CHECK JS_IR NATIVE:
+//   Mangled name: #bar2(kotlin.String){}
+//   Public signature: /bar2|871846488143355822[0]
+fun bar2(s: String): Int
+
+// CHECK:
+//   Mangled name: #bar3(){}
+//   Public signature: /bar3|-4458378888622542195[0]
+fun bar3(): Unit
+
+// CHECK JVM_IR:
+//   Mangled name: #bar3(kotlin.String){}kotlin.Int
+//   Public signature: /bar3|-5694254873370624097[0]
+// CHECK JS_IR NATIVE:
+//   Mangled name: #bar3(kotlin.String){}
+//   Public signature: /bar3|-8604784325283105439[0]
+suspend fun bar3(s: String): Int
+
+// CHECK:
+//   Mangled name: #box(){}
+//   Public signature: /box|2173511048851971368[0]
+fun box(): Unit
+
+// CHECK:
+//   Mangled name: #foo1(SuspendRunnable){}
+//   Public signature: /foo1|-5121966172672447653[0]
+fun foo1(s: SuspendRunnable): Unit
+