RISC-V: Extend VLS modes in 'VWEXTI' iterator

RISC-V: Extend VLS modes in 'VWEXTI' iterator

This patch extends 'VWEXT' iterator so that we will support
integer extension/integer truncate/integer average VLS patterns.

This patch reduce these following FAILs:

FAIL: gcc.dg/pr92301.c execution test
XPASS: gcc.dg/vect/bb-slp-subgroups-3.c -flto -ffat-lto-objects  scan-tree-dump-times slp2 "optimized: basic block" 2
XPASS: gcc.dg/vect/bb-slp-subgroups-3.c scan-tree-dump-times slp2 "optimized: basic block" 2

The pr92301.c is the latent bug in middle-end GIMPLE FOLD.
We are just lucky that this test passes with this patch which makes us not trigger the GIMPLE FOLD bug again.

gcc/ChangeLog:

	* config/riscv/riscv-v.cc (can_find_related_mode_p): New function.
	(vectorize_related_mode): Add VLS related modes.
	* config/riscv/vector-iterators.md: Extend VLS modes.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/binop/narrow-1.c: Adapt testcase.
	* gcc.target/riscv/rvv/autovec/binop/narrow-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/narrow-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/cmp/vcond-1.c: Ditto.
	* gcc.target/riscv/rvv/autovec/cmp/vcond-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/cmp/vcond-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/cmp/vcond-4.c: Ditto.
	* gcc.target/riscv/rvv/autovec/partial/slp-18.c: Ditto.
	* gcc.target/riscv/rvv/autovec/partial/slp-19.c: Ditto.
	* gcc.target/riscv/rvv/autovec/pr110950.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-1.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-10.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-11.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-12.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-4.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-5.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-6.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-7.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-9.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-1.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-10.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-11.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-12.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-4.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-5.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-6.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-7.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-9.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vls/def.h: Ditto.
	* gcc.target/riscv/rvv/autovec/vls/div-1.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vls/shift-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-1.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-4.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-5.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-6.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-7.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-9.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-complicate-1.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-complicate-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-complicate-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-complicate-4.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-complicate-5.c: Ditto.
	* gcc.target/riscv/rvv/autovec/widen/widen-complicate-6.c: Ditto.
	* gcc.target/riscv/rvv/autovec/zve32f-1.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vls/avg-1.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/avg-2.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/avg-3.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/avg-4.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/avg-5.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/avg-6.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/ext-1.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/ext-2.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/ext-3.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/trunc-1.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/trunc-2.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/trunc-3.c: New test.