Rollup merge of #148363 - alexcrichton:fix-wasm-link-name, r=jackh726

Fix `wasm_import_module` attribute cross-crate

This commit fixes an accidental regression from rust-lang/rust#144678 where wasm targets would now accidentally use the wrong import module map for a symbol causing a symbol to skip mangling. This can result in compilation failures when symbols are used in cross-crate situations.

Closes rust-lang/rust#148347