[perl #131911] [BUG] non-Perl 6 scripts in the module bin directory do not install in a runnable form

[via RT]

# New Ticket Created by  Christopher Bottoms 
# Please include the string:  [perl #131911]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=131911 >


(This may be easier to read here: https://github.com/ugexe/zef/issues/200. The 
only reason it is closed there is because it is a Rakudo bug, not a zef bug)

## Context

In the module directory is a `META6.json` file and a subdirectory called `bin`. 
In the `bin` is a Perl 5 file called `bin/test.pl`.

`zef install .` runs without error in the top directory. But when trying to run 
`test.pl`, I get an error. Come to find out, a Perl 6 wrapper script had been 
installed for `test.pl` and that is what is giving me the error. If I run 
`bin/test.pl` directly, it works fine.

## Expected Behavior

I expected that running `test.pl` from any directory would be the same as 
running it from the source directory.

## Actual Behavior

When trying to run `test.pl`, I get the following error:

    ===SORRY!===
    Could not find Perl5 at line 2 in:
        /home/username/.perl6
        /path/to/perl6/rakudo-star-2017.07/install/share/perl6/site
        /path/to/perl6/rakudo-star-2017.07/install/share/perl6/vendor
        /path/to/perl6/rakudo-star-2017.07/install/share/perl6
        CompUnit::Repository::AbsolutePath<64730416>
        CompUnit::Repository::NQP<43359856>
        CompUnit::Repository::Perl5<43359896>

## Steps to Reproduce

Create the following files:

**`META6.json`**

    {
    "perl"         : "6.c",
    "name"         : "TESTING1234",
    "license"      : "Artistic-2.0",
    "version"      : "0.0.2",
    "auth"         : "github:author",
    "authors"      : ["First Last"],
    "description"  : "TESTING module creation",
    "provides"     : {
                     },
    "depends"      : [ ],
    "test-depends" : [ "Test", "Test::META"  ]
    }

**`bin/test.pl`**

    #!/bin/env perl
    use v5.10;
    use strict;
    use warnings;

    say 'Hello world!';

Install it and run `test.pl`.

```
zef install .
test.pl     # error
bin/test.pl # works fine
```

The "installed" `test.pl` script is
`/path/to/perl6/rakudo-star-2017.07/install/share/perl6/site/bin/test.pl`:
    #!/usr/bin/env perl6
    sub MAIN(:$name is copy, :$auth, :$ver, *@, *%) {
        CompUnit::RepositoryRegistry.run-script("test.pl", 
:dist-name<TESTING1234>, :$name, :$auth, :$ver);
    }


## Your Environment
* perl6 -v
```
This is Rakudo version 2017.07 built on MoarVM version 2017.07
implementing Perl 6.c.
```

Thank you for all of your hard work!