test: add test for gcc issue with weak hidden symbol on powerpc

On Ubuntu 32-bit powerpc, gcc 4.4, 4.6, 4.8, gcc -O1 (and O2) causes
weak hidden symbols to have different addresses within the same module.
It seems to be fixed in gcc 4.9 on powerpc.

This issue causes some tracepoints to be silently hidden from LTTng.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>