Unrolled build for #152116

Rollup merge of #152116 - GuillaumeGomez:fix-rustdoc-gui-flaky, r=GuillaumeGomez

Remove rustdoc GUI flaky test

Part of #93784.

Originally, this test was checking more things (original version is [here](6bbbff5)), now it only checks that the `searchIndex` variable is global. However, we already are forced to check it in the `rustddoc-js[-std]` testsuites so I think it's safe to say that it's superfluous and definitely not worth all the CI flakyness it created.

r? ghost

Author: rust-timer