Allow ProcessStartInfo and Process.Start arguments to be null

[campersau]

The arguments in ProcessStartInfo / Process.Start are currently not allowed to be null but it is ok if they are null.
E.g.

runtime/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessStartInfo.cs

Line 52 in 35b1dd2

public ProcessStartInfo(string fileName, string arguments)

runtime/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.cs

Line 1316 in 35b1dd2

public static Process Start(string fileName, string arguments)

[stephentoub]

but it is ok if they are null

What do you mean?

[campersau]

but it is ok if they are null

What do you mean?

That nothing throws when arguments is null.