58891 [flutter_tools] rename library to be less absurd (cla: yes, tool, waiting for tree to go green)

58893 Roll Engine from c0365be2ab70 to bd7dd73b4744 (3 revisions) (cla: yes, waiting for tree to go green)

58899 Roll Engine from bd7dd73b4744 to 5709dc531814 (1 revision) (cla: yes, waiting for tree to go green)

58903 Roll Engine from 5709dc531814 to 3f224d8e861f (2 revisions) (cla: yes, waiting for tree to go green)