Use constants for filenames in build_spec.rb

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

spec/ee/spec/models/ee/ci/build_spec.rb

@@ -129,9 +129,9 @@ describe Ci::Build do
   end
 
   ARTIFACTS_METHODS = {
-    has_codeclimate_json?: 'codeclimate.json',
-    has_performance_json?: 'performance.json',
-    has_sast_json?: 'gl-sast-report.json'
+    has_codeclimate_json?: Ci::Build::CODEQUALITY_FILE,
+    has_performance_json?: Ci::Build::PERFORMANCE_FILE,
+    has_sast_json?: Ci::Build::SAST_FILE
   }.freeze
 
   ARTIFACTS_METHODS.each do |method, filename|