AIDEGen: Updates XML file by xml.etree.ElementTree

1. Create a XML util to parse a XML file.
2. Check if the XML file's content has the specific elements for
   IntelliJ.
3. Append the new <jdk> element under the <component>.
4. Update the XML file by xml.etree.ElementTree.ElementTree.write().

Bug: 151582629
Test: 1. sh run_tests.sh
      2. Keep the code coverage of changes 100%.
Change-Id: Idcbe08070277601f10ca155d17b6ae8d985b09f3
6 files changed