[Tizen] Add xwalk-launcher support for full app exec path cmdline

Currently the AUL service can't find correct app info by using
/proc/<pid>/cmdline when app is launched with xwalk-launcher
method. It needs full app exec path to query the corresponding app info.

This patch will change argv to full exec path when app launched with
xwalk-launcher <app-id>.

BUG=XWALK-1722
Merge pull request #1967 from seanlong/xwalk-1722

[Tizen] Add xwalk-launcher support for full app exec path cmdline