Fix invalid d8 runtime

[kfarnung]

The combination of #50 and #51 has resulted in the d8 runtime being invalid because the single-line comments remove all following code when newlines are removed.

The fix is to always build the AST and remove comments, regardless of whether the shortName is being replaced.

[kfarnung]

Here's what I'm seeing with the latest NPM version:

> eshost -tse "3+4"
┌────────────────┬──────────────────────────────────────┐
│ V8             │                                      │
│ V8 --harmony   │ SyntaxError: Unexpected end of input │
├────────────────┼──────────────────────────────────────┤
│ Chakra         │ 7                                    │
│ JavaScriptCore │                                      │
│ SpiderMonkey   │                                      │
│ XS             │                                      │
└────────────────┴──────────────────────────────────────┘

[kfarnung]

With this fix:

> node .\bin\eshost.js -tse "3+4"
┌────────────────┬───┐
│ Chakra         │ 7 │
│ JavaScriptCore │   │
│ SpiderMonkey   │   │
│ V8             │   │
│ V8 --harmony   │   │
│ XS             │   │
└────────────────┴───┘

[rwaldron]

Squash merged: https://github.com/bterlson/eshost/commit/a0f16713b903292f966fcfd579b15cdc955b0429

Thanks!