Remove CommonBackendContext.getInternalClass

Move to subclasses: getJvmInternalClass, getJsInternalClass and
getKonanInternalClass (in Kotlin/Native). The advantage of this is that
this API need not be shared between backends any longer, which makes
sense because implementation details differ across platforms

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/CommonBackendContext.kt

@@ -21,9 +21,6 @@ interface LoggingContext {
 interface CommonBackendContext : BackendContext, LoggingContext {
     override val ir: Ir<CommonBackendContext>
 
-    //TODO move to builtins
-    fun getInternalClass(name: String): ClassDescriptor
-
     fun getClass(fqName: FqName): ClassDescriptor
 
     //TODO move to builtins

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/Ir.kt

@@ -64,6 +64,8 @@ abstract class Symbols<out T : CommonBackendContext>(val context: T, private val
 
     abstract val stringBuilder: IrClassSymbol
 
+    abstract val defaultConstructorMarker: IrClassSymbol
+
     val iterator = symbolTable.referenceClass(
         builtInsPackage("kotlin", "collections").getContributedClassifier(
             Name.identifier("Iterator"), NoLookupLocation.FROM_BACKEND
@@ -86,8 +88,6 @@ abstract class Symbols<out T : CommonBackendContext>(val context: T, private val
     val progressionClasses = listOf(charProgression, intProgression, longProgression)
     val progressionClassesTypes = progressionClasses.map { it.descriptor.defaultType }.toSet()
 
-    val defaultConstructorMarker = symbolTable.referenceClass(context.getInternalClass("DefaultConstructorMarker"))
-
     val any = symbolTable.referenceClass(builtIns.any)
     val unit = symbolTable.referenceClass(builtIns.unit)