Re-enable tests with the optimizing compiler.

Tests run ok on my host/target. I reverted the move to
using thumb2, because tests were crashing. But I could not
reproduce file limits issues.

Make SignalTest as crashing for optimizing. We need to implement
stack overflow checks.

Change-Id: Ieda575501eaf30af7aaa2c44e71544c9c467c24f
8 files changed