test_hybrid.cpp: Fix crashing test due to NULL timeval (see below).

The crash is obscure and only appears in certain combinations of compiler and platform.
Revert "test_hybrid.cpp: Fix crashing test due to NULL timeval (see below)."

Change did not address underlying problem.  In particular, while it fixed the issue on clang 3.2, it only shifted it on gcc 4.7.  A NULL timestamp should be legal, so reverting this change.

This reverts commit 5547ef687406006351e51bf2c5a2c1d546a0ca1d.
test_hybrid.cpp: Fix bug where a data structure was allocated on the stack but a pointer to it was retained beyond function return.