Fix wrong code for boolean negation in condition at -O2

Fix wrong code for boolean negation in condition at -O2

The problem is the bitwise/logical dichotomy for operators and the
transition from the former to the latter for boolean types: if they
are 1-bit, that's straightforward but, if they are larger, then you
need to be careful because you cannot, on the one hand, turn a bitwise
AND into a logical AND and, on the other hand, *not* turn e.g. a
bitwise NOT into a logical NOT if they occur in the same computation,
as the first change will drop the masking that may need to be applied
after the bitwise NOT if it is not also changed.

Given that the ranger turns bitwise AND/OR into logical AND/OR for
booleans,  the patch does the same for bitwise NOT.

gcc/ChangeLog:
	* range-op.cc (operator_logical_not::fold_range): Tidy up.
	(operator_logical_not::op1_range): Call above method.
	(operator_bitwise_not::fold_range): If the type is compatible
	with boolean, call op_logical_not.fold_range.
	(operator_bitwise_not::op1_range): If the type is compatible
	with boolean, call op_logical_not.op1_range.

gcc/testsuite/ChangeLog:
	* gnat.dg/opt88.adb: New test.