bitint: Don't move debug stmts from before returns_twice calls [PR114628]

bitint: Don't move debug stmts from before returns_twice calls [PR114628]

Debug stmts are allowed by the verifier before the returns_twice calls.
More importantly, they don't have a lhs, so the current handling of
arg_stmts statements to force them on the edges ICEs.

The following patch just keeps them where they were before.

2024-04-09  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/114628
	* gimple-lower-bitint.cc (gimple_lower_bitint): Keep debug stmts
	before returns_twice calls as is, don't push them into arg_stmts
	vector/move to edges.

	* gcc.dg/bitint-105.c: New test.