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

Test/spv.perprimitiveNV.frag

@@ -0,0 +1,21 @@
+#version 460
+
+#extension GL_NV_mesh_shader: require
+
+layout(location=0) 
+in B {
+    perprimitiveNV float f;
+};
+
+layout(location=4) 
+in C {
+    flat centroid float h;
+};
+
+layout(location=8) 
+out float g;
+
+void main()
+{
+    g = f + h;
+}