[Android] Multiple profile support

Add profile in the path of disk files used to save
user data. Embedder can specify profile by XWalkPreferences.

The profile must be set before any XWalkView instance created
to take effect.

TEST=org.xwalk.core.xwview.test.ProfileTest#testCustomizeProfile
BUG=https://crosswalk-project.org/jira/browse/XWALK-2375