Revert "[cmake] Use `GNUInstallDirs` to support custom installation dirs."

Sorry for the disruption, I will try again later.

This reverts commit efeb50197091b2ade24c00b9d55814bc433a7fd1.

NOKEYCHECK=True
GitOrigin-RevId: 6e52bfe09d3ab3ae6c43c079d06ebeb7bb241dec
1 file changed