Unify test suite total_count

This MR unify the way we calculate the number of total
tests for a given suite.

lib/gitlab/ci/reports/test_suite.rb

@@ -28,7 +28,7 @@ module Gitlab
         def total_count
           return 0 if suite_error
 
-          test_cases.values.sum(&:count)
+          [success_count, failed_count, skipped_count, error_count].sum
         end
         # rubocop: enable CodeReuse/ActiveRecord
 

spec/lib/gitlab/ci/reports/test_suite_spec.rb

@@ -50,9 +50,11 @@ RSpec.describe Gitlab::Ci::Reports::TestSuite do
     before do
       test_suite.add_test_case(test_case_success)
       test_suite.add_test_case(test_case_failed)
+      test_suite.add_test_case(test_case_skipped)
+      test_suite.add_test_case(test_case_error)
     end
 
-    it { is_expected.to eq(2) }
+    it { is_expected.to eq(4) }
   end
 
   describe '#total_status' do