* Generate missing IR parameter declarations in external stubs
* Use origin = FAKE_OVERRIDE in external IR stubs for fake overrides
* Set .parent in external IR stubs
* Set .parent in IR generated by some utility methods
This causes a subtle issue with 'copy' function for data class,
which has parameters with source elements corresponding to
the data class primary constructor parameters: default value expression
for such parameters is generated second time (to be overwritten later),
which creates duplicate bindings if such expression included any
(possibly anonymous) declarations, such as lambdas or anonymous objects.
#KT-18208 Fixed
Dmitry Petrov