Remove some excessive ProcessRequestWork debugging.
Improve DeviceReadBuffer debugging.
Use nothrow new[] to allocate buffer in DRB.

This allows us to handle failures to allocate the potentially large
buffers without the program exiting when compiled with exceptions
enabled (the default).
Reduce # number DeviceReadBuffer::Read() calls.

Refs #11252.

This reduces the number of reads per second we make in the stream handlers
utilizing the DRB. It does this by waiting 20 ms for at least dev_read_size
bytes rather than 500 ms for min_read bytes. The device reads are larger
than the minimum read so this actually results in waiting a bit longer
under normal conditions while returning more quickly when we're not getting
data from the device. A win-win.