Allow GL_NV_mesh_shader in fragment shaders for perprimitiveNV

- Emit relevant capability/extension for use of perprimitiveNV in fragment shader
- Remove redundant checks for mesh shader qualifiers in glslang.y
- Add profile version check for use of extension GL_NV_mesh_shader
- Add a new gtest for use of perprimitiveNV in fragment shader

gtests/Spv.FromFile.cpp

@@ -528,6 +528,7 @@ INSTANTIATE_TEST_CASE_P(
     "spv.meshShaderRedeclBuiltins.mesh",
     "spv.meshShaderRedeclPerViewBuiltins.mesh",
     "spv.meshTaskShader.task",
+    "spv.perprimitiveNV.frag",
 })),
 FileNameAsCustomTestSuffix
 );