Replacing currently broken ICC Latest C++17 with C++14.

[rwgk]

Description

This restores fully functional CI against master.

The C++17 build was working with

• Intel 2021.4.0.20210910 (/opt/intel/oneapi/compiler/2021.4.0/linux/bin/intel64/icpc)

but started failing with

• Intel 2021.5.0.20211109 (/opt/intel/oneapi/compiler/2022.0.0/linux/bin/intel64/icpc)

Related PRs for reporting errors to Intel:

• ICC Latest C++17 (for reporting errors to Intel). #3553
• ICC Latest C++20 (for reporting errors to Intel). #3554

Suggested changelog entry:

[henryiii]

Looks like this is broken again. I'd be fine to roll this back to C++14 for now until Intel gets this fixed. Has it been reported to Intel?

[rwgk]

Trying again in the exact same state to see if the 3.9-dbg (deadsnakes) • Valgrind • x64 failure reproduces.

[rwgk]

Hi @henryiii, I'll revive #3553 after this PR is merged, for reporting to Intel.

[henryiii]

Added a temporary fix for pypa/setuptools#2946.