Fix "Invoke-Item" to accept a file path with spaces on Unix platforms

[daxian-dbw]

Address #2900

Root Cause

On Unix platforms, we are currently depending on xdg-open on Linux and open on OSX to open the default program for a registered file type, so the file path is served as an argument to xdg-open and open. However, we didn't handle the case when path contains spaces.

Fix

Use the method NativeCommandParameterBinder.NeedQuotes, which is used by powershell native command processor, to check if quote is needed. If yes, add quotes in the same way as our native command processor (see the code here).
There is another problem with the current Invoke-Item on Linux and OSX -- it cannot invoke an executable properly. The fix is to first run Process.Start directly with the file path, and if it fails, then try xdg-open or open.

Additional Info

We are focusing on 2 scenarios for "Invoke-Item":

• it can start an executable
• it can open a file with the default program that is registered to the file type.

[adityapatwardhan]

Looks good, except one small comment.

[adityapatwardhan]

Do we need a empty finally block?

[daxian-dbw]

The finally block is kept there for FullCLR section only to match the try block above, so that we don't need to enclose try { and } in if/def. I will add one more comment to make the purpose more clear.
An empty finally block will be ignored during compilation (release version), so there won't be any performance concern. See the code below:

static void Main(string[] args)
{
    Process p = null;
    try { p = new Process(); } finally {  }
}

Corresponding IL

.method private hidebysig static void  Main(string[] args) cil managed
{
  .entrypoint
  // Code size       7 (0x7)
  .maxstack  8
  IL_0000:  newobj     instance void [System.Diagnostics.Process]System.Diagnostics.Process::.ctor()
  IL_0005:  pop
  IL_0006:  ret
} // end of method Program::Main

[iSazonov]

The cmdlet seems to have the most unpredictable behavior😕

[daxian-dbw]

@iSazonov I think we are focusing on 2 scenarios for this cmdlet:

• it can start an executable
• it can open a file with the default program that is registered to the file type.

[iSazonov]

@daxian-dbw Thanks for clarify. Could you move the comment to the PR description for future docs?