RISC-V: Add vector popcount, clz, ctz.

RISC-V: Add vector popcount, clz, ctz.

This patch adds the zvbb vcpop, vclz and vctz to the autovec machinery
as well as tests for them.

gcc/ChangeLog:

	* config/riscv/autovec.md (ctz<mode>2): New expander.
	(clz<mode>2): Ditto.
	* config/riscv/generic-vector-ooo.md: Add bitmanip ops to insn
	reservation.
	* config/riscv/vector-crypto.md: Add VLS modes to insns.
	* config/riscv/vector.md: Add bitmanip ops to mode_idx and other
	attributes.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/unop/popcount-1.c: Adjust check
	for zvbb.
	* gcc.target/riscv/rvv/autovec/unop/popcount-run-1.c: Ditto.
	* gcc.target/riscv/rvv/autovec/unop/popcount-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/unop/popcount-3.c: New test.
	* gcc.target/riscv/rvv/autovec/unop/popcount-template.h: New test.
	* gcc.target/riscv/rvv/autovec/unop/clz-1.c: New test.
	* gcc.target/riscv/rvv/autovec/unop/clz-run.c: New test.
	* gcc.target/riscv/rvv/autovec/unop/clz-template.h: New test.
	* gcc.target/riscv/rvv/autovec/unop/ctz-1.c: New test.
	* gcc.target/riscv/rvv/autovec/unop/ctz-run.c: New test.
	* gcc.target/riscv/rvv/autovec/unop/ctz-template.h: New test.