Fix failed/skipped tests processing by TestNG listener

Hi fellows!
First of all, thanks for great work, your reports look really cool )
We use TestNG as our base test framework, so I found some problems with TestNG listener. Passed tests are processed correctly, but failed and skipped are not. I tested both on our company real project and https://github.com/allure-framework/allure-testng-example by adding some failed/skipped tests.
Here are my fixes, please review. I tested it on 1.2.3 version, cause built by myself 1.3.0-SNAPSHOT version doesn't work.