Improve the gitea importer test

The changes to the tests to support ignoring Gitea pull requests comments were
a bit of a hack. The suggestions provided by Ash McKenzie in
gitlab-org/gitlab-ce!29521 make things a bit more flexible if any future
changes need to be made to the tests.

The changes made to ignore

spec/lib/gitlab/legacy_github_import/importer_spec.rb

@@ -13,27 +13,22 @@ describe Gitlab::LegacyGithubImport::Importer do
 
       expected_called = [
         :import_labels, :import_milestones, :import_pull_requests, :import_issues,
-        :import_wiki, :import_releases, :handle_errors
+        :import_wiki, :import_releases, :handle_errors,
+        [:import_comments, :issues],
+        [:import_comments, :pull_requests]
       ]
 
       expected_called -= expected_not_called
 
       aggregate_failures do
-        expected_called.each do |method_name|
-          expect(importer).to receive(method_name)
+        expected_called.each do |method_name, arg|
+          base_expectation = proc { expect(importer).to receive(method_name) }
+          arg ? base_expectation.call.with(arg) : base_expectation.call
         end
 
-        expect(importer).to receive(:import_comments).with(:issues)
-
-        if expected_not_called.include? :import_comments_pull_requests
-          expect(importer).not_to receive(:import_comments).with(:pull_requests)
-          expected_not_called.delete_at expected_not_called.index :import_comments_pull_requests
-        else
-          expect(importer).to receive(:import_comments).with(:pull_requests)
-        end
-
-        expected_not_called.each do |method_name|
-          expect(importer).not_to receive(method_name)
+        expected_not_called.each do |method_name, arg|
+          base_expectation = proc { expect(importer).not_to receive(method_name) }
+          arg ? base_expectation.call.with(arg) : base_expectation.call
         end
       end
 
@@ -295,7 +290,7 @@ describe Gitlab::LegacyGithubImport::Importer do
     end
 
     it_behaves_like 'Gitlab::LegacyGithubImport::Importer#execute' do
-      let(:expected_not_called) { [:import_releases, :import_comments_pull_requests] }
+      let(:expected_not_called) { [:import_releases, [:import_comments, :pull_requests]] }
     end
     it_behaves_like 'Gitlab::LegacyGithubImport::Importer#execute an error occurs'
     it_behaves_like 'Gitlab::LegacyGithubImport unit-testing'