tests: Fix specialization test

Specialize the correct stage.

Change-Id: I2249d64e6bc2c3fd9dc839d614f4a547573b10cb
diff --git a/tests/vklayertests_pipeline_shader.cpp b/tests/vklayertests_pipeline_shader.cpp
index 86ac530..2ca5dab 100644
--- a/tests/vklayertests_pipeline_shader.cpp
+++ b/tests/vklayertests_pipeline_shader.cpp
@@ -2829,7 +2829,7 @@
 
     const auto set_info = [&](CreatePipelineHelper &helper) {
         helper.shader_stages_ = {helper.vs_->GetStageCreateInfo(), fs.GetStageCreateInfo()};
-        helper.shader_stages_[0].pSpecializationInfo = &specialization_info;
+        helper.shader_stages_[1].pSpecializationInfo = &specialization_info;
     };
     CreatePipelineHelper::OneshotTest(
         *this, set_info, VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXT,