v.io/x/devtools: set JAVA_HOME for android tests
v.io/x/devtools: set JAVA_HOME for android tests

Gradle needs it, sadly.

Change-Id: I00a1597476a2e2d750a90d327df88e8e880d7a36

vanadium/go.devtools,vanadium/go.devtools,vanadium/go.devtools