[FIR] Check top-level property initialization via CFG

Now that files have a CFG, use it to validate properties are initialized
correctly. Update FirTopLevelPropertiesChecker to collect initialization
info for the property being checked - similar to
FirMemberPropertiesChecker - and validate proper initialization.

#KT-56683 Fixed
#KT-58531 Fixed

analysis/analysis-api/testData/components/diagnosticsProvider/diagnostics/declarationErrors.kt

@@ -3,4 +3,7 @@ fun foo(): String
 class A {
   abstract fun foo()
 }
-class B: A
+class B: A
+
+// IGNORE_FIR
+// Does not pass because of KT-61296