Rollup merge of #133605 - traviscross:TC/add-2024-drop-order-tests, r…

…=compiler-errors

Add extensive set of drop order tests

On lang, we've recently been discussing the drop order with respect to `let` chains apropos of how we shortened temporary lifetimes in Rust 2024 and how we may shorten them further in the future.

Here we add an extensive set of tests that demonstrate the drop order in the cases that interest us.

Regarding the let chains stabilization prompting this analysis, see:

- rust-lang/rust#132833

r? ghost

cc `@ehuss` `@dingxiangfei2009` `@nikomatsakis`