Rollup merge of #67065 - alexcrichton:update-wasi, r=sfackler
Rollup merge of #67065 - alexcrichton:update-wasi, r=sfackler

Fix fetching arguments on the wasm32-wasi target

Fixes an error introduced in #66750 where wasi executables always think
they have zero arguments because one of the vectors returned here
accidentally thought it was length 0.

aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust