Add test coverage to podspecs. (#7228)

FirebaseRemoteConfig.podspec

@@ -45,6 +45,7 @@ app update.
   s.dependency 'GoogleUtilities/NSData+zlib', '~> 7.0'
 
   s.test_spec 'unit' do |unit_tests|
+    unit_tests.scheme = { :code_coverage => true }
     # TODO(dmandar) - Update or delete the commented files.
     unit_tests.source_files =
         'FirebaseRemoteConfig/Tests/Unit/FIRRemoteConfigComponentTest.m',
@@ -74,6 +75,7 @@ app update.
 
   # Run Swift API tests on a real backend.
   s.test_spec 'swift-api-tests' do |swift_api|
+    swift_api.scheme = { :code_coverage => true }
     swift_api.platforms = {:ios => '8.0', :osx => '10.11', :tvos => '10.0'}
     swift_api.source_files = 'FirebaseRemoteConfig/Tests/SwiftAPI/*.swift',
                              'FirebaseRemoteConfig/Tests/FakeUtils/*.[hm]',
@@ -89,6 +91,7 @@ app update.
 
   # Run Swift API tests and tests requiring console changes on a Fake Console.
   s.test_spec 'fake-console-tests' do |fake_console|
+    fake_console.scheme = { :code_coverage => true }
     fake_console.platforms = {:ios => '8.0', :osx => '10.11', :tvos => '10.0'}
     fake_console.source_files = 'FirebaseRemoteConfig/Tests/SwiftAPI/*.swift',
                                       'FirebaseRemoteConfig/Tests/FakeUtils/*.[hm]',