Fix jit.dg/test-alignment* (PR jit/82846)

Fix jit.dg/test-alignment* (PR jit/82846)

These testcases jit-compile functions that return char, but
were erroneously calling them as if they returned int.

This led to errors for certain target configurations (e.g.
reading from %eax (32-bit) in the harness when only %al (8-bit)
had been written to in the jit-compiled function).

gcc/testsuite/ChangeLog:
	PR jit/82846
	* jit.dg/test-alignment.c (create_aligned_code): Fix return type
	of "fn_type" typedef.
	* jit.dg/test-alignment.cc (verify_aligned_code): Likewise.

From-SVN: r257037