ipa: fix ICE in get_default_value

The patch aligns code with ipcp_bits_lattice::set_to_constant
where we properly mask m_value with m_mask. The same should
be done here.

gcc/ChangeLog:

	PR ipa/96482
	* ipa-cp.c (ipcp_bits_lattice::meet_with_1): Mask m_value
	with m_mask.

gcc/testsuite/ChangeLog:

	PR ipa/96482
	* gcc.dg/ipa/pr96482-2.c: New test.