[IR] In irText tests, test full mangled names only computed from IR

We plan to disable computing full mangled names of declarations in all
manglers except the IR mangler (see the subsequent commits).

From now on, in irText tests we dump only the following mangled names:

- Full mangled names computed using the IR mangler
- Signature mangled names computed using the Descriptor mangler
- Signature mangled names computed using the IR mangler
- Signature mangled names computed using the FIR mangler

Here by a full mangled name we mean the mangled name of a declaration
computed using the `MangleMode.FULL` mode. Those mangled names include
the mangled names of the declaration'a parents.

By a signature mangled name we mean the mangled name of a declaration
computed using the `MangleMode.SIGNATURE` mode.
These mangled names are used to compute an `IdSignature` for
the declaration, hence the name.

compiler/testData/ir/irText/firProblems/localClassUsedBeforeDeclaration.sig.kt.txt

@@ -9,50 +9,66 @@
 fun box(): String
   // CHECK JVM_IR:
   //   Mangled name: #box(){}kotlin.String.<no name provided>
+  //   Mangled name for the signature: box(){}kotlin.String
   // CHECK JS_IR NATIVE:
   //   Mangled name: #box(){}.<no name provided>
+  //   Mangled name for the signature: box(){}
   local class <no name provided> {
     // CHECK JVM_IR:
     //   Mangled name: #box(){}kotlin.String.<no name provided>{}a
+    //   Mangled name for the signature: box(){}kotlin.String{}a
     // CHECK JS_IR NATIVE:
     //   Mangled name: #box(){}.<no name provided>{}a
+    //   Mangled name for the signature: box(){}{}a
     val a: A
       field
       // CHECK JVM_IR:
       //   Mangled name: #box(){}kotlin.String.<no name provided>#<get-a>(){}#box.<no name provided>.A
+      //   Mangled name for the signature: box(){}kotlin.String<get-a>(){}#box.<no name provided>.A
       // CHECK JS_IR NATIVE:
       //   Mangled name: #box(){}.<no name provided>#<get-a>(){}
+      //   Mangled name for the signature: box(){}<get-a>(){}
       get
 
     // CHECK JVM_IR:
     //   Mangled name: #box(){}kotlin.String.<no name provided>.A
+    //   Mangled name for the signature: box(){}kotlin.String
     // CHECK JS_IR NATIVE:
     //   Mangled name: #box(){}.<no name provided>.A
+    //   Mangled name for the signature: box(){}
     local inner class A {
       // CHECK JVM_IR:
       //   Mangled name: #box(){}kotlin.String.<no name provided>.A{}ok
+      //   Mangled name for the signature: box(){}kotlin.String{}ok
       // CHECK JS_IR NATIVE:
       //   Mangled name: #box(){}.<no name provided>.A{}ok
+      //   Mangled name for the signature: box(){}{}ok
       val ok: String
         field
         // CHECK JVM_IR:
         //   Mangled name: #box(){}kotlin.String.<no name provided>.A#<get-ok>(){}kotlin.String
+        //   Mangled name for the signature: box(){}kotlin.String<get-ok>(){}kotlin.String
         // CHECK JS_IR NATIVE:
         //   Mangled name: #box(){}.<no name provided>.A#<get-ok>(){}
+        //   Mangled name for the signature: box(){}<get-ok>(){}
         get
 
       // CHECK JVM_IR:
       //   Mangled name: #box(){}kotlin.String.<no name provided>.A#<init>(kotlin.String){}
+      //   Mangled name for the signature: box(){}kotlin.String<init>(kotlin.String){}
       // CHECK JS_IR NATIVE:
       //   Mangled name: #box(){}.<no name provided>.A#<init>(kotlin.String){}
+      //   Mangled name for the signature: box(){}<init>(kotlin.String){}
       constructor(ok: String) /* primary */
 
     }
 
     // CHECK JVM_IR:
     //   Mangled name: #box(){}kotlin.String.<no name provided>#<init>(){}
+    //   Mangled name for the signature: box(){}kotlin.String<init>(){}
     // CHECK JS_IR NATIVE:
     //   Mangled name: #box(){}.<no name provided>#<init>(){}
+    //   Mangled name for the signature: box(){}<init>(){}
     constructor() /* primary */
 
   }