Converted gen emitter tests to gtest, and removed the old testing framework from core

test/teststruct.h

@@ -1,20 +0,0 @@
-#pragma once
-
-#include <string>
-
-#define YAML_ASSERT(cond)               \
-  do {                                  \
-    if (!(cond))                        \
-      return "  Assert failed: " #cond; \
-  } while (false)
-
-namespace Test {
-struct TEST {
-  TEST() : ok(false) {}
-  TEST(bool ok_) : ok(ok_) {}
-  TEST(const char *error_) : ok(false), error(error_) {}
-
-  bool ok;
-  std::string error;
-};
-}