Fix: add file name in stack traces for compiled classes

[andreabergia]

In interpreter mode, we always put the file name, but in compiled mode we do it only in case of compilerEnv.isGenerateDebugInfo(). I think that the interpreter's behavior is much more useful, so I changed the compiler to always include the file name.

For an example of the difference, create two files:

one.js

const two = require('./two');
two();

and two.js:

module.exports = function() {
	throw new Error('hey')
}

Then launch the shell passing -version 200 -opt -1 -require one.js to get the following, useful stack trace:

js: "file:/Users/andrea.bergia/src/rhino/two.js", line 2: exception from uncaught JavaScript throw: Error: hey
	at file:/Users/andrea.bergia/src/rhino/two.js:2
	at file:/Users/andrea.bergia/src/rhino/one.js:2

But with -opt 0 we get:

js: "file:/Users/andrea.bergia/src/rhino/two.js", line 2: exception from uncaught JavaScript throw: Error: hey
	at (unknown):2 (anonymous)
	at (unknown):2

which isn't as useful.

[gbrail]

I can't think of why anyone wouldn't want this, but let's see if anyone pops up and has questions.