Remove ANDROID_BUILD_TOP from intelliJ path variables. [DO NOT MERGE]

The variable is not actually needed and it makes working with different
API levels a lot easier since everything now depends on $PROJECT_DIR$.

This change also makes the tests more robust by improving the way it
tries to find the SDK.

Change-Id: I3502ad4a0ba85fd88b497e47964fddb2a89e520c
(cherry picked from commit 5377695d4ecf3cc6dc1abe59bbfca63f6137b722)