[IR] Remove methods for computing full mangled names from non-IR manglers

A full mangled name of a declaration is a mangled name that includes
the mangled names of all the declaration's parents.

We don't use full mangled names for building `IdSignature`s. We use them
in two places:
- Generating stable names for JavaScript functions in Kotlin/JS
  (see `NameTables.kt`)
- Generating names for LLVM symbols from lowered IR functions in
  Kotlin/Native (see `BinaryInterface.kt`)

In both of these places we run the IR mangler, hence we don't need this
functionality in other manglers.

compiler/ir/serialization.jvm/src/org/jetbrains/kotlin/backend/jvm/serialization/DisabledIdSignatureDescriptor.kt

@@ -20,17 +20,8 @@ object DisabledDescriptorMangler : KotlinMangler.DescriptorMangler {
     override fun DeclarationDescriptor.isExported(compatibleMode: Boolean): Boolean =
         error("Should not be called")
 
-    override fun DeclarationDescriptor.mangleString(compatibleMode: Boolean): String =
-        error("Should not be called")
-
     override fun DeclarationDescriptor.signatureString(compatibleMode: Boolean): String =
         error("Should not be called")
-
-    override fun ClassDescriptor.mangleEnumEntryString(compatibleMode: Boolean): String =
-        error("Should not be called")
-
-    override fun PropertyDescriptor.mangleFieldString(compatibleMode: Boolean): String =
-        error("Should not be called")
 }
 
 object DisabledIdSignatureDescriptor : IdSignatureDescriptor(DisabledDescriptorMangler) {