Some code cleaning

[mawHBT]

• Extracted duplicated code in GradleBuildfileEditor
• TestTaskParser was named integrationTestTaskProperties, even if method was called for testTask, so I renamed it to just testTaskParser

[DaGeRe]

Thanks for the PR. While this is overall fine, method names should not contain or (in addTestOrIntegrationTestBlock). I'd recommend to name it just addTestPhaseBlock or something like this.

[mawHBT]

Renamed GradleBuildfileEditor.addTestOrIntegrationTestBlock to addTestPhaseBlock

[DaGeRe]

Looks fine, thanks for the PR!