Merge beta-accepted into beta

[alexcrichton]

This is a backport of:

• resolve: Improve duplicate glob detection #32814
• Release notes for 1.9 #32892
• Compute LLVM-agnostic type layouts in rustc. #32939
• trans: always register an item's symbol, even if duplicated. #32946
• resolve: Improve performance #33064

Additionally, this bumps the beta version to .2 so we can produce a new beta.

[rust-highfive]

r? @pnkfelix

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[rust-highfive]

Warning

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