Tests: Fix RunCMake.try_compile C/CXX standards with IntelLLVM MSVC mode

Since !6319 (merged) we activate C/C++ standard level logic for IntelLLVM when targeting the MSVC ABI. Update the RunCMake.try_compile test to be aware of this even when CMake is itself configured by an older CMake that does not know this.

Also fix the 3.20 backport of !6319 (merged) by also backporting commit 7596d8b9 from !5783 (merged).

Backport: release

changed milestone to %3.21.0

added comp:intel-llvm workflow:in-review labels

Warnings:

• Eligible for the 3.21.x branch.

The warnings do not need to be fixed, but it is recommended to do so.

mentioned in merge request !6319 (merged)

Cc: @williamr

Do: stage

mentioned in merge request !6177 (merged)

added workflow:nightly-testing label and removed workflow:in-review label

Do: merge

merged

mentioned in commit 5df2c458

mentioned in commit 89b61d91

removed workflow:nightly-testing label

mentioned in commit 9029335b

RunCMake.try_compile on Windows-IntelLLVM-2021-Ninja still seems to be broken?

resolved all threads