Fix simd_gather intrinsic #4246

Job	Run time
rustfmt	12s
test_llvm	3m 56s
test (ubuntu-latest, x86_64-unknown-linux-gnu)	12m 14s
bench	8m 28s
test (ubuntu-24.04-arm, aarch64-unknown-linux-gnu)	9m 26s
test (ubuntu-latest, riscv64gc-unknown-linux-gnu, gcc-riscv64-linux-gnu qemu-user)	5m 44s
test (macos-15-intel, x86_64-apple-darwin)	21m 4s
test (windows-latest, x86_64-pc-windows-msvc)	19m 36s
dist (ubuntu-22.04, x86_64-unknown-linux-gnu)	2m 57s
dist (ubuntu-24.04-arm, aarch64-unknown-linux-gnu)	2m 41s
test (ubuntu-latest, s390x-unknown-linux-gnu, gcc-s390x-linux-gnu qemu-user)	7m 14s
dist (macos-latest, aarch64-apple-darwin)	2m 42s
test (macos-latest, aarch64-apple-darwin)	13m 2s
dist (macos-15-intel, x86_64-apple-darwin)	6m 17s
dist (windows-latest, x86_64-pc-windows-gnu)	5m 26s
test (windows-latest, x86_64-pc-windows-gnu)	25m 35s
dist (windows-latest, x86_64-pc-windows-msvc)	4m 40s
release	18s
	2h 31m 32s

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