Putting the test code in the same package makes it easier for forks
since they don't have to change the import paths as much and it also
gets rid of the need for internal_test.go to bridge.
This same thing should probably be done for the majority of the code
base.
This modifies the chaincfg package to register the default network
params via the init function instead of manually hard coding their data
into the maps. This is less error prone when adding new default
networks.
A new function named mustRegister has been introduced that panics if
there are any errors when registering the network that the new code
makes use of and appropriate tests have been added.
