gfauto: skip extraction of GLSL shaders (#1131)
gfauto: skip extraction of GLSL shaders (#1131)

Add GLSL to the list of shader types that we skip when extracting shaders. gfauto can extract shaders from AmberScript files for execution via offline shader compilers and other tools, like spirv-opt. We only want to extract SPIRV-ASM shaders.
google/graphicsfuzz,google/graphicsfuzz,google/graphicsfuzz,google/graphicsfuzz,google/graphicsfuzz,google/graphicsfuzz,google/graphicsfuzz