0x0
means you're attempting to initialize an already initialized account. What's happening here is that because your PDAs have only constant seeds, the same address is generated for them on each run of the test.
Therefore, not only does running your test for the first time initializesinitialize pdaGlobalAccount
and pdaEscrow
and any attempt to run your, but subsequent tests after that failsalso fail because it triesthey would attempt to initialize the same accounts as the first because(because constant seeds give you the exact same address each time).