Remove testing::Environment leftover (#2471)

tests/gtest/avif_fuzztest_helpers.cc

@@ -248,28 +248,6 @@ size_t GetNumSamples(size_t num_frames, size_t width, size_t height,
          (num_luma_samples + num_chroma_samples + num_alpha_samples);
 }
 
-//------------------------------------------------------------------------------
-// Environment setup
-
-namespace {
-class Environment : public ::testing::Environment {
- public:
-  Environment(const char* name, const char* value)
-      : name_(name), value_(value) {}
-  void SetUp() override {
-#ifdef _WIN32
-    _putenv_s(name_, value_);  // Defined in stdlib.h.
-#else
-    setenv(name_, value_, /*overwrite=*/1);
-#endif
-  }
-
- private:
-  const char* name_;
-  const char* value_;
-};
-}  // namespace
-
 //------------------------------------------------------------------------------
 
 std::vector<std::string> GetSeedDataDirs() {