Download stable build info from gcs

[aditya-wazir]

Retrieves stable build info for the Cuttlefish branch and target by downloading build info from stable_build_info.json from gcs.

[jonathanmetzman]

Can you run the formatter please.

[jonathanmetzman]

/gcbrun

[svasudevprasad]

/gcbrun

[svasudevprasad]

/gcbrun

[marktefftech]

Looks like there is a centipede-related unit test failing, but it's not clear whether or not this breakage is associated with this change:

Traceback (most recent call last):
  File "/workspace/src/clusterfuzz/_internal/tests/core/bot/fuzzers/centipede/centipede_engine_test.py", line 388, in test_minimize_corpus
    self.assertLess(len(os.listdir(minimized_corpus)), 6)
AssertionError: 6 not less than 6