Rollup of 7 pull requests

[matthiaskrgr]

Successful merges:

• Add T-bootstrap label to tools #107236 (Add T-bootstrap label to tools)
• Only create graphviz nodes for reachable MIR bb's #109847 (Only create graphviz nodes for reachable MIR bb's)
• submodule detection for proper fix on #96188 #109848 (submodule detection for proper fix on rustc build broken after #95906 #96188)
• Source code scrollbar #109932 (Source code scrollbar)
• Move comment about python2 closer to the place it's used #109952 (Move comment about python2 closer to the place it's used)
• Tweak debug outputs to make debugging new solver easier #109956 (Tweak debug outputs to make debugging new solver easier)
• Add regression test for #80409 #109968 (Add regression test for ICE infering higher-ranked lifetime with a builder pattern #80409)

Failed merges:

r? @ghost
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