[FIR] Report UNINITIALIZED_VARIABLE for top-level properties

When checking top-level properties, check with initialization enabled.
This makes sure the same errors are reported for member and top-level
properties.

compiler/testData/diagnostics/tests/controlFlowAnalysis/UninitializedOrReassignedVariables.fir.kt

@@ -255,7 +255,7 @@ class Outer() {
 }
 
 class ForwardAccessToBackingField() { //kt-147
-    val a = <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM, UNINITIALIZED_VARIABLE!>a<!> // error
+    val a = <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM!>a<!> // error
     val b = <!UNINITIALIZED_VARIABLE!>c<!> // error
     val c = 1
 }

compiler/testData/diagnostics/tests/controlFlowAnalysis/propertiesOrderInPackage.fir.kt

@@ -1,4 +0,0 @@
-package a
-
-val a : Int = b
-val b : Int = a

compiler/testData/diagnostics/tests/controlFlowAnalysis/propertiesOrderInPackage.kt

@@ -1,4 +1,5 @@
+// FIR_IDENTICAL
 package a
 
 val a : Int = <!UNINITIALIZED_VARIABLE!>b<!>
-val b : Int = a
+val b : Int = a

compiler/testData/diagnostics/tests/controlFlowAnalysis/repeatUnitializedErrorOnlyForLocalVars.fir.kt

@@ -1,7 +1,7 @@
 package aa
 
-val a : Int = b
-val b : Int = a + b
+val a : Int = <!UNINITIALIZED_VARIABLE!>b<!>
+val b : Int = a + <!UNINITIALIZED_VARIABLE!>b<!>
 
 class C {
     val a : Int = <!UNINITIALIZED_VARIABLE!>b<!>