crypto: use CHECK instead in getSSLCiphers

The previous throws should never happen, and if they do, they
signal a larger issue in core. Make these checks rather than
throws.

src/node_crypto.cc

@@ -5618,15 +5618,10 @@ void GetSSLCiphers(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
 
   SSL_CTX* ctx = SSL_CTX_new(TLSv1_server_method());
-  if (ctx == nullptr) {
-    return env->ThrowError("SSL_CTX_new() failed.");
-  }
+  CHECK_NE(ctx, nullptr);
 
   SSL* ssl = SSL_new(ctx);
-  if (ssl == nullptr) {
-    SSL_CTX_free(ctx);
-    return env->ThrowError("SSL_new() failed.");
-  }
+  CHECK_NE(ssl, nullptr);
 
   Local<Array> arr = Array::New(env->isolate());
   STACK_OF(SSL_CIPHER)* ciphers = SSL_get_ciphers(ssl);