[wlan] Fix use-after-free in TimElement unit test

The vector is freed when FindAndParseTim() returns since the vector is
instantiated as an argument to the function. This change keeps the
vector in memory so the checks following the function call can safely
access the vector's contents.

Test: Test now passes on ASan garnet build.

Change-Id: I96338cf2fc8819c14d93f02d7492db4578a6a57d
1 file changed