Handle search paths better

[ptomato]

This situation will not be handled correctly:

jasmine.json

{
  "spec_files": [ "path1", "path2" ]
}

path1/test.js

describe('A suite', function () {});

path2/test.js

describe('Another suite', function () {});

In this case, only "A suite" gets run and not "Another suite" because path1 and path2 are both added to imports.searchPath. When Jasmine goes to import test twice, then path1/test.js fulfills the requirement both times.