codec_unittest.cc: Fix TEST vs TEST_F mismatch

This CL fixes a typo introduced in "Revert of H264 codec: Check profile-level-id when matching" https://codereview.webrtc.org/2440123002/.

BUG=NONE
TBR=kthelgason

Review URL: https://codereview.webrtc.org/2450743002 .

Cr-Commit-Position: refs/heads/master@{#14760}
diff --git a/webrtc/media/base/codec_unittest.cc b/webrtc/media/base/codec_unittest.cc
index 7ad9733..5388004 100644
--- a/webrtc/media/base/codec_unittest.cc
+++ b/webrtc/media/base/codec_unittest.cc
@@ -183,7 +183,7 @@
   EXPECT_FALSE(c1.Matches(VideoCodec(95, "V")));
 }
 
-TEST(CodecTest, TestDataCodecMatches) {
+TEST_F(CodecTest, TestDataCodecMatches) {
   // Test a codec with a static payload type.
   DataCodec c0(95, "D");
   EXPECT_TRUE(c0.Matches(DataCodec(95, "")));