Remove temporary _test_crypto directory

_test_crypto/bux.toml

@@ -1 +0,0 @@
-[Package]

_test_crypto/src/Main.bux

@@ -1,18 +0,0 @@
-import Std::Io::{PrintLine};
-import Std::Crypto;
-
-func Main() -> int {
-    PrintLine("SHA256:");
-    PrintLine(Crypto_Sha256("hello"));
-    
-    PrintLine("HMAC-SHA256:");
-    PrintLine(Crypto_HmacSha256("secret", "message"));
-    
-    PrintLine("Base64 encode:");
-    PrintLine(Crypto_Base64Encode("hello"));
-    
-    PrintLine("Random bytes (base64):");
-    PrintLine(Crypto_RandomBytes(16));
-    
-    return 0;
-}