Fixed flaky RenderScript VTS Test

Added missing synchronization before context destroy

Bug: 62535730
Bug: 38385848
Test: make vts, does not fail with multiple tests
Change-Id: Ib0d038969e9a1d6f5ea555ccb60fed55b69e05dc
(cherry picked from commit 076f69aa2bc2301e3c93150503d469c02ed2458c)
1 file changed