thorium: some actions can not be optimized in delivery paths

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
genomics: big messages hog CPUs for too long

On Blue Gene/Q, we can see that messages are accumulating:

thorium_node: node/981 MESSAGES ReceivedMessageCount: 1147499 SentMessageCount: 1249302 BufferedInboundMessageCount: 26682 ActiveRequestCount: 0
thorium_node: node/364 MESSAGES ReceivedMessageCount: 1131213 SentMessageCount: 1229511 BufferedInboundMessageCount: 29651 ActiveRequestCount: 0

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>