Modify the frame context memory deallocation

This patch was to fix the vpxdec fuzzing3 test failure. When an
error occurs, setjmp() is invoked, which calls the decoder
removing routine. In multiple thread situation, other threads
could try to access the frame context memory that is already
deallocated, thus causing a segfault.

An invalid unit test was added for this issue.

Change-Id: Ida7442154f3d89759483f0f4fe0324041fffb952
Merge "Modify the frame context memory deallocation"