Frog can't handle multi-line strings in library directives

[DartBot]

This issue was originally filed by ms...@unipro.ru

---

What steps will reproduce the problem?
Specification defines the library directive as:
“#” “library” “(” stringLiteral “)” “;”
This definition does not prohibit from using multi-line string literals. However, the following test is generated into invalid Javascript:

library('''lib

rary''');

main() {
  print('Ok');
}

What is the expected output? What do you see instead?
Expected: 'Ok'
Actual: /tmp/tmpSbZ15W/out.js:157
rary **************
      ^

node.js:201
        throw e; // process.nextTick error, or 'error' event on first tick
              ^
SyntaxError: Unexpected token *
    at Module._compile (module.js:423:12)
    at Object..js (module.js:459:10)
    at Module.load (module.js:348:31)
    at Function._load (module.js:308:12)
    at Array.0 (module.js:479:10)
    at EventEmitter._tickCallback (node.js:192:40)

What version of the product are you using? On what operating system?
frog, r4304. OS: Ubuntu 10.04

Please provide any additional information below.

[kasperl]

Added Area-Frog, Triaged labels.

[anders-sandholm]

Removed Area-Frog label.
Added Area-Dart2JS, FromAreaFrog labels.

[kasperl]

Added WontFix label.