Fix PR rtl-optimization/113140

This is a small regression present on the mainline and 13 branch, although the underlying problem has probably been there for ages, in the form of a segfault during the delay slot scheduling pass, for a function that falls through to exit without any RTL instruction generated for the end of func

Fix PR rtl-optimization/113140

This is a small regression present on the mainline and 13 branch, although the underlying problem has probably been there for ages, in the form of a segfault during the delay slot scheduling pass, for a function that falls through to exit without any RTL instruction generated for the end of func