Rollup merge of #147710 - chenyukang:yukang-fix-ice-contracts-async, r=jackh726

Fix ICE when using contracts on async functions

Fixes rust-lang/rust#145333

contract is not supported for async functions right now, it's not properly lowered and getting HirId will ICE.

This PR adds checking for async function in expanding AST phase, it's better until we want to fully support async for contracts feature.

Author: matthiaskrgr