Drop "Reflection types not loaded" diagnostic

Reflection types are now considered to be built-in, so their absence means the
runtime is broken and the compiler can't work at all; this condition probably
should be handled on another level for all built-in types

compiler/testData/diagnostics/tests/deprecated/genericConstructorUsage.kt

@@ -1,4 +1,4 @@
-// !DIAGNOSTICS: -UNUSED_EXPRESSION, -REFLECTION_TYPES_NOT_LOADED, -UNUSED_PARAMETER
+// !DIAGNOSTICS: -UNUSED_EXPRESSION, -UNUSED_PARAMETER
 
 open class C<T>() {
     deprecated("")