Factor out bits of the worker protocol to use elsewhere
(cherry picked from commit 4b1a97338f517f45e6169d3d8845c5caa5724e97)
Change-Id: If93afa0f8b1cf9b0e705b34fa71e6fd708752758
Enable most of the third `BuildResult` worker protocol test
(cherry picked from commit d344c112f772282bacacd4c66a75df4022d16e12)
Change-Id: I7b2b72aa84c19a6069f9c12128d901262db6f91c
Test the rest of the worker protocol serializers
(cherry picked from commit 2f1c16dfa2378fd8616bff1b9b7cd0b4d42af69b)
Change-Id: Idfd72d32b21d14a260e02f65531d287cef7464d2
Unit test some worker protocol serializers
(cherry picked from commit c6faef61a6f31c71146aee5d88168e861df9a22a)
Change-Id: I99e36f5f17eb7642211a4e42a16b143424f164b4