media/gpu/video_encode_accelerator_tests: Rename bitrate check test cases

This CL changes the name of bitrate check test cases, so that
they have the common prefix, "Bitrate." This helps to understand
the tests checks bitrates and also runs only the bitrate check
tests.

pBug: None
Test: video_encode_accelerator_tests --gtest_filter=VideoEncoderTest.BitrateCheck*
Change-Id: I4ae5a3a68702341b4661965dc39967bad23240d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2519334
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Auto-Submit: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: David Staessens <dstaessens@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824288}

media/gpu/video_encode_accelerator_tests.cc

@@ -316,7 +316,7 @@ TEST_F(VideoEncoderTest, BitrateCheck) {
               kBitrateTolerance * config.bitrate);
 }
 
-TEST_F(VideoEncoderTest, DynamicBitrateChange) {
+TEST_F(VideoEncoderTest, BitrateCheck_DynamicBitrate) {
   auto config = GetDefaultConfig();
   config.num_frames_to_encode = kNumFramesToEncodeForBitrateCheck * 2;
   auto encoder = CreateVideoEncoder(g_env->Video(), config);
@@ -347,7 +347,7 @@ TEST_F(VideoEncoderTest, DynamicBitrateChange) {
   EXPECT_TRUE(encoder->WaitForBitstreamProcessors());
 }
 
-TEST_F(VideoEncoderTest, DynamicFramerateChange) {
+TEST_F(VideoEncoderTest, BitrateCheck_DynamicFramerate) {
   auto config = GetDefaultConfig();
   config.num_frames_to_encode = kNumFramesToEncodeForBitrateCheck * 2;
   auto encoder = CreateVideoEncoder(g_env->Video(), config);