TMethodCallExpr.IsConstructorCall (TypeName.Create with args) was missing
the storel $vtable_X instruction after _ClassAlloc. The TFieldAccessExpr
path (no-arg Create) already had it. The missing store left vtable pointer
as zero, causing _IsInstance to crash with null vtable dereference during
type analysis of TTypeDesc subclasses.
Also adds virtual Destroy to TTypeDesc in the hand source so TTypeDesc and
its subclasses (TRecordTypeDesc, TEnumTypeDesc, TInterfaceTypeDesc) get
vtable slots, making HasVTable return true and field offsets correct.
Regression tests added for both the no-arg and with-arg constructor vtable
store paths.
f6ac68f537