debug: Use G_UNLIKELY in the tests
debug: Use G_UNLIKELY in the tests

Debugging code is not meant to be run in the nominal code path. Use
G_UNLIKELY to be reduce the number of bubbles in the instruction
pipeline.

Took the opportunity to re-indent the macros.

gcampax/cogl,djdeath/cogl-android,Distrotech/cogl,spatulasnout/cogl,collects/cogl,djdeath/cogl,collects/cogl,spatulasnout/cogl,gcampax/cogl,djdeath/cogl-android,djdeath/cogl,djdeath/cogl-android,Distrotech/cogl,Distrotech/cogl,gcampax/cogl,Distrotech/cogl,djdeath/cogl,gcampax/cogl