Add support for dynamic loading of EGL entry points

This change adds eglu::Library abstraction for accessing any and all EGL
entry points. All code has been changed to use that interface instead of
calling EGL functions directly.

Having code use abstract interface instead of direct entry points allows
always builing EGL code paths and dynamically loading them if supported
by the environment. In the future analysis and logging facilities could
be layered on that interface.

This change required lots of small changes across all EGL code. As part
of that refactoring work tcu::egl utilities were finally put to rest for
good. All uses of glw.h were also removed from the EGL module.

Bug: 18269587
Change-Id: Ic81e24b7eecb9813d00fba5c65144d4f59a550e8
127 files changed