Fixed tests issue where vertex shader was misssing gl_PointSize

Affects:
dEQP-VK.protected_memory.ssbo.*

Components: Vulkan

VK-GL-CTS issue:: 915

Change-Id: Ia7cc2b9a6b1593ca15f585a9dc052cb2528f9ee3
diff --git a/external/vulkancts/modules/vulkan/protected_memory/vktProtectedMemStorageBufferTests.cpp b/external/vulkancts/modules/vulkan/protected_memory/vktProtectedMemStorageBufferTests.cpp
index 34e8ba2..25f416a 100644
--- a/external/vulkancts/modules/vulkan/protected_memory/vktProtectedMemStorageBufferTests.cpp
+++ b/external/vulkancts/modules/vulkan/protected_memory/vktProtectedMemStorageBufferTests.cpp
@@ -258,6 +258,7 @@
 		"void main() {\n"
 		"    vec2 pos[4] = vec2[4]( vec2(-0.7, 0.7), vec2(0.7, 0.7), vec2(0.0, -0.7), vec2(-0.7, -0.7) );\n"
 		"    vIndex = vec4(gl_VertexIndex);\n"
+		"    gl_PointSize = 1.0;\n"
 		"    gl_Position = vec4(pos[gl_VertexIndex], 0.0, 1.0);\n"
 		"}";