[Ada] Fix discrepancy in mechanism tracking private and full views

[Ada] Fix discrepancy in mechanism tracking private and full views

This fixes a discrepancy in the mechanism tracking the private and full
views of entities when entering and leaving scopes.  This mechanism
records private entities that are dependent on other private entities,
so that the exchange done on entering and leaving scopes can be
propagated.

The propagation is done recursively on entering child units, but it was
not done recursively on leaving them, which would leave the dependency
chains in a uncertain state in this case.  That's mostly visible when
inlining across units is enabled for code involving a lot of generic
units.

2019-08-14  Eric Botcazou  <ebotcazou@adacore.com>

gcc/ada/

	* sem_ch7.adb (Install_Private_Declarations)
	<Swap_Private_Dependents>: Do not rely solely on the
	Is_Child_Unit flag on the unit to recurse.
	(Uninstall_Declarations) <Swap_Private_Dependents>: New
	function.  Use it to recurse on the private dependent entities
	for child units.

gcc/testsuite/

	* gnat.dg/inline18.adb, gnat.dg/inline18.ads,
	gnat.dg/inline18_gen1-inner_g.ads, gnat.dg/inline18_gen1.adb,
	gnat.dg/inline18_gen1.ads, gnat.dg/inline18_gen2.adb,
	gnat.dg/inline18_gen2.ads, gnat.dg/inline18_gen3.adb,
	gnat.dg/inline18_gen3.ads, gnat.dg/inline18_pkg1.adb,
	gnat.dg/inline18_pkg1.ads, gnat.dg/inline18_pkg2-child.ads,
	gnat.dg/inline18_pkg2.ads: New testcase.

From-SVN: r274451