glsl: Don't abbreviate tessellation shader stage names.

glsl: Don't abbreviate tessellation shader stage names.

I have a patch that writes shaders as .shader_test files, and it uses
this function to create the headers (i.e. [vertex shader]).

[tess ctrl shader] isn't a valid shader_runner header - it's spelled
out as [tessellation control shader].

There's no real reason to abbreviate it, so spell it out.

v2: Rebase on Rob's patches to move the code.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>