random: Call int-seeding functions directly

As the `__construct()` implementation is engine-specific anyway, we know what
engine were dealing with and can just call the seeding function directly
instead of going through a function pointer.

This likely improves construction performance a little, but I did not measure.

ext/random/engine_mt19937.c

@@ -282,7 +282,7 @@ PHP_METHOD(Random_Engine_Mt19937, __construct)
 		}
 	}
 
-	engine->algo->seed(engine->status, seed);
+	mt19937_seed_state(state, seed);
 }
 /* }}} */
 

ext/random/engine_pcgoneseq128xslrr64.c

@@ -177,7 +177,7 @@ PHP_METHOD(Random_Engine_PcgOneseq128XslRr64, __construct)
 				RETURN_THROWS();
 			}
 		} else {
-			engine->algo->seed(engine->status, int_seed);
+			seed128(state, php_random_uint128_constant(0ULL, (uint64_t) int_seed));
 		}
 	}
 }

ext/random/engine_xoshiro256starstar.c

@@ -246,7 +246,7 @@ PHP_METHOD(Random_Engine_Xoshiro256StarStar, __construct)
 				RETURN_THROWS();
 			}
 		} else {
-			engine->algo->seed(engine->status, (uint64_t) int_seed);
+			seed64(state, (uint64_t) int_seed);
 		}
 	}
 }