FIR checker: report SUPERTYPE_NOT_INITIALIZED

Combined this and the checker of
SUPERTYPE_INITIALIZED_WITHOUT_PRIMARY_CONSTRUCTOR together.

Also fixed SUPERTYPE_INITIALIZED_WITHOUT_PRIMARY_CONSTRUCTOR incorrectly
repoted as warning instead of error.

compiler/fir/analysis-tests/testData/resolve/diagnostics/conflictingOverloads.kt

@@ -16,7 +16,7 @@ fun test(z: Int, c: Char) {}
 
 }<!>
 
-<!REDECLARATION!>class B : A {
+<!REDECLARATION!>class B : <!SUPERTYPE_NOT_INITIALIZED!>A<!> {
     <!CONFLICTING_OVERLOADS!>override fun rest(s: String)<!> {}
 
     <!CONFLICTING_OVERLOADS!>fun rest(s: String)<!> {}