`tests/rustdoc-js` can't be run at stage 0

[jieyouxu]

but

if i run the test with --stage 1, then back with --stage 0, it works correctly.

looks like build artifacts are not being isolated enough or something??

Originally posted by @lolbinarycat in #135595 (comment)

[jieyouxu]

I'm fairly sure rustdoc contributors usually only use ./x test rustdoc-js --stage 1 🤔 At --stage 0 this fails with

---- [rustdoc-js] tests/rustdoc-js/search-non-local-trait-impl.rs stdout ----

error: rustdoc-js test failed!
status: exit status: 1
command: "/home/joe/.local/share/nvm/v23.6.0/bin/node" "/home/joe/repos/rust/src/tools/rustdoc-js/tester.js" "--doc-folder" "/home/joe/repos/rust/build/x86_64-unknown-linux-gnu/test/rustdoc-js/search-non-local-trait-impl" "--crate-name" "search_non_local_trait_impl" "--test-file" "/home/joe/repos/rust/tests/rustdoc-js/search-non-local-trait-impl.js"
--- stdout -------------------------------
Error: Cannot find module '/home/joe/repos/rust/build/x86_64-unknown-linux-gnu/test/rustdoc-js/search-non-local-trait-impl/search-index.js'
Require stack:
- /home/joe/repos/rust/src/tools/rustdoc-js/tester.js
    at Function._resolveFilename (node:internal/modules/cjs/loader:1409:15)
    at defaultResolveImpl (node:internal/modules/cjs/loader:1060:19)
    at resolveForCJSWithHooks (node:internal/modules/cjs/loader:1065:22)
    at Function._load (node:internal/modules/cjs/loader:1214:37)
    at TracingChannel.traceSync (node:diagnostics_channel:322:14)
    at wrapModuleLoad (node:internal/modules/cjs/loader:234:24)
    at Module.require (node:internal/modules/cjs/loader:1495:12)
    at require (node:internal/modules/helpers:135:16)
    at loadSearchJS (/home/joe/repos/rust/src/tools/rustdoc-js/tester.js:403:25)
    at main (/home/joe/repos/rust/src/tools/rustdoc-js/tester.js:552:28) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [ '/home/joe/repos/rust/src/tools/rustdoc-js/tester.js' ]
}
------------------------------------------
stderr: none

But running --stage 1 then --stage 0 again passes, which measn that something required is built at stage 1 but not stage 0, and that whatever that thing is isn't properly stamped.

[jieyouxu]

cc @rust-lang/rustdoc: do you know if this test suite was ever intended to be possible to run at --stage 0?

[lolbinarycat]

related: #135597