[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/kt36956.kt

@@ -1,3 +1,6 @@
+// MUTE_SIGNATURE_COMPARISON_K2: ANY
+// ^ KT-57429
+
 class A<T>(private val value: T) {
     operator fun get(i: Int) = value
     operator fun set(i: Int, v: T) {}
@@ -5,4 +8,4 @@ class A<T>(private val value: T) {
 
 val aFloat = A<Float>(0.0f)
 
-val aInt = (aFloat[1])--
+val aInt = (aFloat[1])--