On this platform, when doing stack allocation, MAP_STACK is needed
 otherwise the mapping fails.

… on an impl trait

According to the release notes and its PR milestone, it was stabilized
in 1.56.0.

…, r=jackh726

Don't normalize xform_ret_ty during method candidate assembly

Fixes rust-lang#85671

Normalizing the return type of a method candidate together with the expected receiver type of the method can lead to valid method candidates being rejected during probing. Specifically in the example of the fixed issue we have a `self_ty` of the form `&A<&[Coef]>` whereas the `impl_ty` of the method would be `&A<_>`, if we normalize the projection in the return type we unify the inference variable with `Cont`, which will lead us to reject the candidate in the sup type check in `consider_probe`. Since we don't actually need the normalized return type during candidate assembly, we postpone the normalization until we consider candidates in `consider_probe`.

stack overflow handler specific openbsd change.

… r=estebank

Remove textual span from diagnostic string

This is an unnecessary repetition, as the diagnostic prints the span anyway in the source path right below the message.

I further removed the identification of the node, as that does not give any new information in any of the cases that are changed in tests.

EDIT: also inserted a suggestion that other diagnostics were already emitting

Fix stabilization version for `bindings_after_at`

According to the release notes and its PR milestone, it was stabilized
in 1.56.0.

…anager_on_s390x_take_two, r=nagisa

Default to disabling the new pass manager for the s390x arch targets.

This hack disables the new LLVM pass manager by default for s390x arch targets until the performance issues are fixed (see rust-lang#89609). The command line option `-Z new-llvm-pass-manager=(yes|no)` continues to take precedence over this default.

Cfg hide more conditions for core and alloc

Fixes rust-lang#89663

Before:
![image](https://user-images.githubusercontent.com/3616612/136572816-a7844ac7-dc2f-4d79-87b4-7f9766421a83.png)

After:
![image](https://user-images.githubusercontent.com/3616612/136572745-7d890726-8efd-4d74-83ac-ed06f4687741.png)

*Same for alloc*

r? `@GuillaumeGomez`