Normalize _unittest.cc filename suffix for unittests

mojo/mojo_public.gypi

 {
   'targets': [
     {
       'target_name': 'mojo_system',
       'type': 'shared_library',
       'defines': [
         'MOJO_SYSTEM_IMPLEMENTATION',
       ],
       'include_dirs': [
         '..',
@@ skipping 41 matching lines @@
       ],
       'sources': [
         'public/tests/bindings/array_unittest.cc',
         'public/tests/bindings/connector_unittest.cc',
         'public/tests/bindings/handle_passing_unittest.cc',
         'public/tests/bindings/remote_ptr_unittest.cc',
         'public/tests/bindings/type_conversion_unittest.cc',
         'public/tests/bindings/buffer_unittest.cc',
         'public/tests/bindings/math_calculator.mojom',
         'public/tests/bindings/sample_factory.mojom',
-        'public/tests/bindings/sample_service_unittests.cc',
+        'public/tests/bindings/sample_service_unittest.cc',
         'public/tests/bindings/test_structs.mojom',
       ],
       'includes': [ 'public/bindings/mojom_bindings_generator.gypi' ],
     },
     {
       'target_name': 'mojo_public_environment_unittests',
       'type': 'executable',
       'dependencies': [
         '../base/base.gyp:base',
         '../testing/gtest.gyp:gtest',
@@ skipping 119 matching lines @@
         'public/utility/thread_local.h',
         'public/utility/thread_local_posix.cc',
         'public/utility/thread_local_win.cc',
       ],
       'include_dirs': [
         '..',
       ],
     },
   ],
 }