LoongArch: Add tests for ASX vector xvbitclr/xvbitclri/xvbitrev/xvbitrevi/ xvbitsel/xvbitseli/xvbitset/xvbitseti/xvclo/xvclz/xvpcnt instructions.
gcc/testsuite/ChangeLog:
* gcc.target/loongarch/vector/lasx/lasx-xvbitclr.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvbitclri.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvbitrev.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvbitrevi.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvbitsel.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvbitseli.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvbitset.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvbitseti.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvclo.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvclz.c: New test.
* gcc.target/loongarch/vector/lasx/lasx-xvpcnt.c: New test.