Initialize GL even when HWUI is running Vulkan

Even though more and more devices are running Vulkan, many apps still
use GL, instead of or in addition to using HWUI. Initialize GL as part
of the zygote step. This only happens once at boot - new app processes
won't do this again, so it speeds up app startup time. And since it
happens before forking the zygote, it starts off in shared memory. If an
app never uses GL, it won't have to use any memory for this GL state.

Use a new static method on Properties, rather than a static bool, as is
done for several other properties, because this happens before loading
other properties.

Bug: 335172671
Test: manual verification via log statements
Flag: initialize_gl_always
Change-Id: I80b366121db0034131afb656ea774e37171f223b