test: Expand upload tests with fake_forge

[jerry-skydio]

Now that we have a forge abstraction, we can improve
test coverage in upload. Add a fake forge class that
tracks query / update data in memory and a bunch of
tests that exercise the various flags.

[jerry-skydio]

Reviews in this chain:
└#249 forge: Genericize github handling into a forge abstraction
　└#250 test: Expand upload tests with fake_forge
　　└#253 github: Add graphql utility class to contain query fields
　　　└#254 github: Add request retry splitting

[jerry-skydio]

#	head	base	diff	date	summary
0	48d65d5d	bd7abad6	diff	May 19 18:34 PM	2 files changed, 744 insertions(+)
1	0c04e95d	bd7abad6	diff	May 20 13:52 PM	1 file changed, 306 insertions(+), 2 deletions(-)
2	d68e6ac2	98287168	rebase	May 20 14:15 PM	0 files changed
3	4599c0ba	98287168	diff	May 20 14:42 PM	2 files changed, 67 insertions(+), 84 deletions(-)