FIR checker: report uninitialized member/extension properties

compiler/tests-spec/testData/diagnostics/linked/declarations/classifier-declaration/class-declaration/abstract-classes/p-1/neg/1.1.fir.kt

@@ -8,8 +8,8 @@ abstract class Base() {
     <!ABSTRACT_FUNCTION_WITH_BODY!>abstract<!> fun foo() = {}
     <!NON_ABSTRACT_FUNCTION_WITH_NO_BODY!>fun boo() : Unit<!>
     abstract val a = <!ABSTRACT_PROPERTY_WITH_INITIALIZER!>""<!>
-    val b
-    var d
+    <!MUST_BE_INITIALIZED_OR_BE_ABSTRACT!>val b<!>
+    <!MUST_BE_INITIALIZED_OR_BE_ABSTRACT!>var d<!>
 }
 
 class Impl : Base() {