Migrate SkRTConfRegistry test to DEF_TEST().

src/utils/SkRTConf.cpp

Index: src/utils/SkRTConf.cpp
diff --git a/src/utils/SkRTConf.cpp b/src/utils/SkRTConf.cpp
index bb6cb23cb93c366d29f6bc961907b2a83cece592..6d5eafd8025f477b3dbcfd1d5a9d7fff93dc734d 100644
--- a/src/utils/SkRTConf.cpp
+++ b/src/utils/SkRTConf.cpp
@@ -325,26 +325,8 @@ SkRTConfRegistry &skRTConfRegistry() {
 
 #ifdef SK_SUPPORT_UNITTEST
 
-#ifdef SK_BUILD_FOR_WIN32
-static void sk_setenv(const char* key, const char* value) {
-    _putenv_s(key, value);
-}
-#else
-static void sk_setenv(const char* key, const char* value) {
-    setenv(key, value, 1);
-}
-#endif
-
-void SkRTConfRegistry::UnitTest() {
-    SkRTConfRegistry registryWithoutContents(true);
-
-    sk_setenv("skia_nonexistent_item", "132");
-    int result = 0;
-    registryWithoutContents.parse("nonexistent.item", &result);
-    SkASSERT(result == 132);
-}
-
-SkRTConfRegistry::SkRTConfRegistry(bool)
+SkRTConfRegistry::SkRTConfRegistry()
     : fConfs(100) {
 }
+
 #endif