Replace GLSL as the default OpenGL shader backend

GLASM is not very compatible with the latest games, and too many people have the special superpower to break their Vulkan support.

src/common/settings.h

@@ -442,7 +442,7 @@ struct Values {
     SwitchableSetting<NvdecEmulation> nvdec_emulation{NvdecEmulation::GPU, "nvdec_emulation"};
     SwitchableSetting<bool> accelerate_astc{true, "accelerate_astc"};
     SwitchableSetting<bool> use_vsync{true, "use_vsync"};
-    SwitchableSetting<ShaderBackend, true> shader_backend{ShaderBackend::GLASM, ShaderBackend::GLSL,
+    SwitchableSetting<ShaderBackend, true> shader_backend{ShaderBackend::GLSL, ShaderBackend::GLASM,
                                                           ShaderBackend::SPIRV, "shader_backend"};
     SwitchableSetting<bool> use_asynchronous_shaders{false, "use_asynchronous_shaders"};
     SwitchableSetting<bool> use_fast_gpu_time{true, "use_fast_gpu_time"};