Mark vx and vxe as important hwcap to be able to provide differently tuned shared libraries.

Please pick the glibc commit "S390: Mark vx and vxe as important hwcap.". This commit is already cherry-picked to glibc 2.29 release branch: https://sourceware.org/git/?p=glibc.git;a=commit;h=6eb48fe80cb6dd3ef536e86d005976d1c22b170e.
Note: This commit is also cherry-picked to glibc 2.27, 2.28 release branches.

This commit allows to have a library (e.g. libatlas) with different tunings, e.g. one with vx- and another one with vxe-instructions. With this patch, glibc chooses the "best" available version depending on the hwcaps reported by the kernel.

The correct locations for the different tuned libraries are:
-for z14 with vxe-support: /usr/lib/s390x-linux-gnu/vxe/
-for z13 with vx-support: /usr/lib/s390x-linux-gnu/vx/
-for all without vector-support: /usr/lib/s390x-linux-gnu/

As information:
One could also place the libraries into z13 or z14 subfolders. But e.g. if you run on a z13 and vector support is disabled (e.g. by specified kernel-parameter), the "z13" library with vector instructions is chosen - which is NOT allowed!

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---Steps to Reproduce---
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Userspace tool common name: glibc

Userspace rpm: libc6

The userspace tool has the following bit modes: both

Userspace tool obtained from project website: na

*Additional Instructions for :
-Attach ltrace and strace of userspace application.