ANDROID: vulkan: allow building Vulkan without libcompiler

Modify the meson and source files to allow building without
the compiler.

gfxstream-vulkan forwards the shader to the host, and doesn't
need to convert into NIR in the guest.  This results in faster
builds and less parts of Mesa to build.  Also venus does the
same thing too, that's what the build is keyed on right now
as an in-tree user.

Bug: 327408955
Test: compile
Change-Id: Idd9529cf3dca54156bb42458b414d1937e674855
5 files changed