PREMIUMAPP-854: NPLB Test- SbMediaCanPlayMimeAndKeySystem.ValidatePerformance failure

Reason for change: Caching supported decorders in platform for passing
SbMediaCanPlayMimeAndKeySystem.ValidatePerformance nplb test.

Test Procedure: Refer ticket
Risks: None
Signed-off-by: Vaisakh Anand <vaisakh_anand@comcast.com>
Change-Id: I6fee781957eed50121e17bc5eacc1758eedba481