refactor: rename testbench to test.

- rename testbench to test.
- add benchmark for future development.

test/yycc/macro/endian_detector.cpp

@@ -0,0 +1,18 @@
+#include <gtest/gtest.h>
+#include <yycc.hpp>
+#include <yycc/macro/endian_detector.hpp>
+
+#define ENDIAN ::yycc::macro::endian
+
+namespace yycctest::macro::endian {
+
+    TEST(MacroEndian, Main) {
+        auto rv = ENDIAN::get_endian();
+#if defined(YYCC_ENDIAN_LITTLE)
+        EXPECT_EQ(rv, ENDIAN::EndianKind::Little);
+#else
+        EXPECT_EQ(rv, ENDIAN::EndianKind::Big);
+#endif
+    }
+
+} // namespace yycctest::macro::endian