fsi incorrect handling of some script arguments

Consider script test_args.fsx:
```
printfn "%A" fsi.CommandLineArgs
```

When execing:
```
>dotnet fsi test_args.fsx -r -f
[|"test_args.fsx"; "-r:-f"|]
```
When using:
```
>dotnet fsi --use:test_args.fsx -- -- -r -f

Microsoft (R) F# Interactive version 14.0.101.0 for F# 10.0
Copyright (c) Microsoft Corporation. All Rights Reserved.

For help type #help;;

> [|"test_args.fsx"; "-r:-f"|]
val it: unit = ()
```

From looking over `fsi.fs`, it seems that `PostProcessCompilerArgs` is called before any other command line processing. This will find the '-r' and treat it as an abbreviated `--reference` option, combining it with its "argument" into a single `-r:-f`. Perhaps, rather than the initial `PostProcessCompilerArgs`, the check for a space-separated arg for `-r` (for example) could be added to the main loop in `ParseCompilerOptions`.