Raise deprecation level for map delegation accessor according to #KT-18789

#KT-21703

libraries/stdlib/src/kotlin/collections/MapAccessors.kt

@@ -35,7 +35,7 @@ public inline operator fun <V, V1 : V> Map<in String, @Exact V>.getValue(thisRef
 public inline operator fun <V, V1 : V> MutableMap<in String, out @Exact V>.getValue(thisRef: Any?, property: KProperty<*>): V1 =
     @Suppress("UNCHECKED_CAST") (getOrImplicitDefault(property.name) as V1)
 
-@Deprecated("Use getValue() with two type parameters instead")
+@Deprecated("Use getValue() with two type parameters instead", level = DeprecationLevel.ERROR)
 @kotlin.jvm.JvmName("getVarContravariant")
 @kotlin.internal.LowPriorityInOverloadResolution
 @kotlin.internal.InlineOnly

libraries/stdlib/test/properties/delegation/MapAccessorsTest.kt

@@ -72,11 +72,11 @@ class VarByMapExtensionsTest {
     @Test fun deprecatedAccessors() {
         assertEquals<Int>(
             expected = map.getValue(this, VarByMapExtensionsTest::c),
-            actual = map.getValue<Int>(this, VarByMapExtensionsTest::c)
+            actual = @Suppress("DEPRECATION_ERROR") map.getValue<Int>(this, VarByMapExtensionsTest::c)
         )
         assertEquals<String>(
             expected = map2.getValue<CharSequence, String>(this, VarByMapExtensionsTest::a2),
-            actual = map2.getValue<String>(this, VarByMapExtensionsTest::a2)
+            actual = @Suppress("DEPRECATION_ERROR") map2.getValue<String>(this, VarByMapExtensionsTest::a2)
         )
     }
 }