target/i386: Rewrite simple integer vector helpers

target/i386: Rewrite simple integer vector helpers

Rewrite the "simple" vector integer helpers in preperation for AVX support.

While the current code is able to use the same prototype for unary
(a = F(b)) and binary (a = F(b, c)) operations, future changes will cause
them to diverge.

No functional changes to existing helpers

Signed-off-by: Paul Brook <paul@nowt.org>
Message-Id: <20220424220204.2493824-12-paul@nowt.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>