Use --concurrency with brew fetch

This should hopefully make CI just a little bit faster. It'll help us
kick the tires on `--concurrency`.

lib/tests/bottles_fetch.rb

@@ -31,7 +31,9 @@ def fetch_bottles!(formula_name, args:)
 
  tags.each do |tag|
  cleanup_during!(args:)
- test "brew", "fetch", "--retry", "--formulae", "--bottle-tag=#{tag}", formula_name
+ test "brew", "fetch", "--retry", "--formulae", "--bottle-tag=#{tag}",
+ "--concurrency", Homebrew::EnvConfig.make_jobs,
+ formula_name
  end
  end
  end

lib/tests/formulae.rb

@@ -151,11 +151,16 @@ def setup_formulae_deps_instances(formula, formula_name, args:)
 
  dependencies -= installed
  @unchanged_dependencies = dependencies - @testing_formulae
- test "brew", "fetch", "--formulae", "--retry", *@unchanged_dependencies unless @unchanged_dependencies.empty?
+ unless @unchanged_dependencies.empty?
+ test "brew", "fetch", "--formulae", "--retry",
+ "--concurrency", Homebrew::EnvConfig.make_jobs,
+ *@unchanged_dependencies
+ end
 
  changed_dependencies = dependencies - @unchanged_dependencies
  unless changed_dependencies.empty?
  test "brew", "fetch", "--formulae", "--retry", "--build-from-source",
+ "--concurrency", Homebrew::EnvConfig.make_jobs,
  *changed_dependencies
 
  ignore_failures = !args.test_default_formula? && changed_dependencies.any? do |dep|
@@ -453,7 +458,7 @@ def formula!(formula_name, args:)
  install_ca_certificates_if_needed
 
  if (messages = unsatisfied_requirements_messages(formula))
- test "brew", "fetch", "--formula", "--retry", *fetch_args
+ test "brew", "fetch", "--formula", "--retry", "--concurrency", Homebrew::EnvConfig.make_jobs, *fetch_args
  test "brew", "audit", "--formula", *audit_args
 
  skipped formula_name, messages
@@ -485,7 +490,7 @@ def formula!(formula_name, args:)
 
  info_header "Starting tests for #{formula_name}"
 
- test "brew", "fetch", "--formula", "--retry", *fetch_args
+ test "brew", "fetch", "--formula", "--retry", "--concurrency", Homebrew::EnvConfig.make_jobs, *fetch_args
 
  env = {}
  env["HOMEBREW_GIT_PATH"] = nil if deps.any? do |d|

lib/tests/formulae_dependents.rb

@@ -253,14 +253,16 @@ def install_dependent(dependent, testable_dependents, args:, build_from_source:
 
  build_args << "--build-from-source"
 
- test "brew", "fetch", "--build-from-source", "--retry", dependent.full_name
+ test "brew", "fetch", "--build-from-source", "--retry",
+ "--concurrency", Homebrew::EnvConfig.make_jobs,
+ dependent.full_name
  return if steps.last.failed?
  else
  fetch_formulae << dependent.full_name
  end
 
  if fetch_formulae.present?
- test "brew", "fetch", "--retry", *fetch_formulae
+ test "brew", "fetch", "--retry", "--concurrency", Homebrew::EnvConfig.make_jobs, *fetch_formulae
  return if steps.last.failed?
  end