May make sense that both `FromHumanSize()` and `RAMInBytes()` support
the same units. Added 'PB' to the RAMInBytes regex.
Also updated tests.
Note: int64 is overflowed on quantities >= EB
Docker-DCO-1.1-Signed-off-by: Francisco Carriedo <fcarriedo@gmail.com> (github: fcarriedo)
Upstream-commit: 0fd37bd7ac0f92eda0a55cf2bedf77f1996b8472
Component: engine