[FE] Prohibit open val deferred initialization

^KT-57553 Fixed
Review: https://jetbrains.team/p/kt/reviews/9967

Other related tests:
- testUninitializedOrReassignedVariables
- testUseOfPropertiesWithoutPrimary
- @TestMetadata("compiler/testData/diagnostics/tests/secondaryConstructors")
- testAugmentedAssignmentInInitializer
- testInitOpenSetter
- testInitOverrideInConstructorComplex
- testPropertyInitializationOrder

compiler/frontend/cfg/src/org/jetbrains/kotlin/cfg/ControlFlowInformationProviderImpl.kt

@@ -619,7 +619,6 @@ class ControlFlowInformationProviderImpl private constructor(
         if (variableDescriptor !is PropertyDescriptor
             || ctxt.enterInitState?.mayBeInitialized() == true
             || ctxt.exitInitState?.mayBeInitialized() != true
-            || !variableDescriptor.isVar
             || trace.get(BACKING_FIELD_REQUIRED, variableDescriptor) != true
         ) {
             return false