Replace LuaTable.Node with flat arrays

Rather than having a Node[] array, we now have separate arrays for keys,
values and the next slot. This allows for slightly less pointer chasing
and arguably better cache locality - never sure how much we can do that
in Java!

Valhalla can't come soon enough :(.

build.gradle.kts

@@ -175,3 +175,10 @@ tasks.test {
 		events("skipped", "failed")
 	}
 }
+
+val benchmark by tasks.registering(JavaExec::class) {
+	description = "Run our benchmarking suite"
+
+	classpath(sourceSets.test.map { it.runtimeClasspath })
+	mainClass = "cc.tweaked.cobalt.benchmark.BenchmarkFull"
+}