Disabling transform timeout

[crdelsey]

Basic Info

Info	Please fill out this column
Ticket(s) this addresses
Primary OS tested on	Ubuntu 18.04
Primary platform tested on	gazebo simulation turtlebot

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Description of contribution in a few bullet points

• Disabling transform timeout in AMCL. The current ROS2 transform code deadlocks when there is a transform timeout and use_sim_time is active. The timeout clock can't advance because the transform code is in a tight loop, preventing the node from spinning and servicing clock messages.
• It seems it doesn't matter much that AMCL fails to process the laser scans due to missing transform, because occasionally the transform is available, and we can get a fix.

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Future work that may be required in bullet points

Fix AMCL by re-introducing message filters, or finding some other wait to ensure a transform is available when there is laser scan data to process. #171

[SteveMacenski]

Whenever short term solutions like this are implemented, I think its important to add a little comment explaining why and when to reimplement correctly as a TODO. This lets another reader debugging issues down the line find the root cause easily if this is forgotten about.

[crdelsey]

Good idea. I was thinking of this as removing a short term workaround rather than adding, so I didn't think to add the comment. I'll fix.

[mhpanah]

LGTM.