`tests/rustdoc-gui/impl-block-doc.goml` seems flaky under CI

[jieyouxu]

Instance: #155607 (comment)

======== tests/rustdoc-gui/impl-block-doc.goml ========
[ERROR] impl-block-doc output:
Runtime.callFunctionOn timed out. Increase the 'protocolTimeout' setting in launch/connect calls for a higher timeout if needed.
stack: ProtocolError: Runtime.callFunctionOn timed out. Increase the 'protocolTimeout' setting in launch/connect calls for a higher timeout if needed.
    at <instance_members_initializer> (/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-gui/node_modules/puppeteer-core/lib/cjs/puppeteer/common/CallbackRegistry.js:103:14)
    at new Callback (/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-gui/node_modules/puppeteer-core/lib/cjs/puppeteer/common/CallbackRegistry.js:107:16)
    at CallbackRegistry.create (/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-gui/node_modules/puppeteer-core/lib/cjs/puppeteer/common/CallbackRegistry.js:25:26)
    at Connection._rawSend (/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-gui/node_modules/puppeteer-core/lib/cjs/puppeteer/cdp/Connection.js:108:26)
    at CdpCDPSession.send (/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-gui/node_modules/puppeteer-core/lib/cjs/puppeteer/cdp/CdpSession.js:74:33)
    at #evaluate (/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-gui/node_modules/puppeteer-core/lib/cjs/puppeteer/cdp/ExecutionContext.js:363:50)
    at ExecutionContext.evaluate (/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-gui/node_modules/puppeteer-core/lib/cjs/puppeteer/cdp/ExecutionContext.js:277:36)
    at IsolatedWorld.evaluate (/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-gui/node_modules/puppeteer-core/lib/cjs/puppeteer/cdp/IsolatedWorld.js:100:30)
    at CdpFrame.evaluate (/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-gui/node_modules/puppeteer-core/lib/cjs/puppeteer/api/Frame.js:362:43)
    at CdpFrame.<anonymous> (/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-gui/node_modules/puppeteer-core/lib/cjs/puppeteer/util/decorators.js:109:27)
<= doc-ui tests done: 143 succeeded, 1 failed, 0 filtered out
Error: ()
Bootstrap failed while executing `test tests/rustdoc-gui --stage 2 --test-args --jobs 1`