analyzer: fix ICE on floating-point bounds [PR111881]

gcc/analyzer/ChangeLog:
	PR analyzer/111881
	* constraint-manager.cc (bound::ensure_closed): Assert that
	m_constant has integral type.
	(range::add_bound): Bail out on floating point constants.

gcc/testsuite/ChangeLog:
	PR analyzer/111881
	* c-c++-common/analyzer/conditionals-pr111881.c: New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>