ovr_multiview: add some basic glsl tests

Part-of: <!984>

tests/spec/ovr_multiview/compiler/multiple-num-views-in-single-declaration-mismatch.vert

+// [config]
+// expect_result: fail
+// glsl_version: 1.30
+// require_extensions: GL_OVR_multiview
+// check_link: false
+// [end config]
+//
+// From the OVR_multiview spec:
+//
+//    "If this layout qualifier is declared more than once in the same shader,
+//    all those declarations must set num_views to the same value; otherwise a
+//    compile-time error results."
+//
+
+#version 130
+#extension GL_OVR_multiview : require
+
+layout(num_views = 3) in;
+layout(num_views = 2) in;
+
+void main() {
+   gl_Position = vec4(1.0);
+}

tests/spec/ovr_multiview/compiler/multiple-num-views-in-single-declaration.vert

+// [config]
+// expect_result: pass
+// glsl_version: 1.30
+// require_extensions: GL_OVR_multiview
+// check_link: false
+// [end config]
+//
+// From the OVR_multiview spec:
+//
+//    "If this layout qualifier is declared more than once in the same shader,
+//    all those declarations must set num_views to the same value; otherwise a
+//    compile-time error results."
+//
+
+#version 130
+#extension GL_OVR_multiview : require
+
+layout(num_views = 3) in;
+layout(num_views = 3) in;
+
+void main() {
+   gl_Position = vec4(1.0);
+}

tests/spec/ovr_multiview/linker/match_viewcount.shader_test

+# If multiple vertex shaders attached to a single program
+# object declare num_views, the declarations must be
+# identical; otherwise a link-time error results.
+
+[require]
+GLSL >= 1.30
+GL_OVR_multiview
+
+[vertex shader]
+#version 130
+#extension GL_OVR_multiview : require
+
+layout(num_views = 2) in;
+
+[vertex shader]
+#version 130
+#extension GL_OVR_multiview : require
+
+layout(num_views = 2) in;
+
+void main() {
+   gl_Position = vec4(1.0);
+}
+
+[test]
+link success

tests/spec/ovr_multiview/linker/mismatch_viewcount.shader_test

+# If multiple vertex shaders attached to a single program
+# object declare num_views, the declarations must be
+# identical; otherwise a link-time error results.
+
+[require]
+GLSL >= 1.30
+GL_OVR_multiview
+
+[vertex shader]
+#version 130
+#extension GL_OVR_multiview : require
+
+layout(num_views = 2) in;
+
+[vertex shader]
+#version 130
+#extension GL_OVR_multiview : require
+
+layout(num_views = 3) in;
+
+void main() {
+   gl_Position = vec4(1.0);
+}
+
+[test]
+link error