Arguments for external executables aren't correctly escaped

Steps to reproduce

1. write a C program native.exe which acquires ARGV
2. Run native.exe "`"a`""

Expected behavior

ARGV[1] == "a"

Actual behavior

ARGV[1] == a

Environment data

Windows 10 x64

Name                           Value
----                           -----
PSVersion                      5.1.14393.0
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.14393.0
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

[be5invis]

Currently to make native.exe correctly receive an ARGV with two quotes and an a character, you have to use this weird call:

native.exe "\`"a\`""

[Artoria2e5]

Making a special operator for this doesn’t make sense for a command-line shell at all, since its main job is to launch programs and pass them arguments. Introducing a new operator that does system() for this job is like Matlab introducing a way to call calc.exe because it has a bug in its arithmetics. What should instead be done is that:

• The pwsh team prepares for a new major release that fixes the command-line stuff, moving the current behavior behind a built-in cmdlet.
• As a stop-gap solution, the upcoming pwsh version gets a built-in cmdlet that uses the new, correct behavior for command-line passing.

The same applies to Start-Process. (Actually it’s a pretty good candidate for the “new” cmdlet with some options like -QuotingBehavior Legacy…) See #13089.