LoongArch: Add tests for ASX vector xvfnmadd/xvfrstp/xvfstpi/xvhsubw/ xvmsub/xvrotr/xvrotri/xvld/xvst instructions.
gcc/testsuite/ChangeLog:
* gcc.target/loongarch/vector/lasx/lasx-xvfnmadd_d.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvfnmadd_s.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvfrstp.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvfrstpi.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvhsubw-1.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvhsubw-2.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvld.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvmsub.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvrotr.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvrotri.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvst.c: New test.