IR: improve toString for symbols

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/symbols/impl/IrPrivateSymbolBase.kt

@@ -29,7 +29,8 @@ abstract class IrSymbolBase<out D : DeclarationDescriptor>(
 
     override fun toString(): String {
         if (isBound) return owner.render()
-        return "Unbound private symbol ${super.toString()}"
+        return "Unbound private symbol " +
+                if (_descriptor != null) "${this::class.java.simpleName}: $_descriptor" else super.toString()
     }
 }
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/symbols/impl/IrPublicSymbolBase.kt

@@ -28,7 +28,7 @@ abstract class IrPublicSymbolBase<out D : DeclarationDescriptor> @OptIn(Obsolete
 
     override fun toString(): String {
         if (isBound) return owner.render()
-        return "Unbound public symbol for $signature"
+        return "Unbound public symbol ${this::class.java.simpleName}: $signature"
     }
 }
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/SymbolTable.kt

@@ -1128,9 +1128,6 @@ val SymbolTable.allUnbound: Set<IrSymbol>
 fun SymbolTable.noUnboundLeft(message: String) {
     val unbound = this.allUnbound
     assert(unbound.isEmpty()) {
-        "$message\n" +
-                unbound.joinToString("\n") {
-                    "${it::class.simpleName} $it ${it.signature?.toString() ?: "(NON-PUBLIC API)"}: ${it.descriptor}"
-                }
+        message + "\n" + unbound.joinToString("\n")
     }
 }