RISC-V: Add regression test for vsetvl bug pr113429

The reduced testcase for pr113429 (cam4 failure) needed additional
modules so it wasn't committed.
The fuzzer found a c testcase that was also fixed with pr113429's fix.
Adding it as a regression test.

	PR target/113429

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/vsetvl/pr113429.c: New test.

Signed-off-by: Patrick O'Neill <patrick@rivosinc.com>