Use java_home to determine jdk location.

Specifying the major version rather than hard coding
to a minor version.

(cherry-picked from commit 13b2e19ef240804908629ed2e54a98ec9dede337)

Change-Id: Ie2c08d35fcff2129b26c1dfa8a2e5cd7b19c4b49
Merge "Use java_home to determine jdk location."
auto-merger: merge in from aosp/master