Use custom radix sort for ordering blocks (#1277)

* Use custom radix sort for ordering blocks

* Licenses :P

* Fix ordering, add test for it

* Grant Gradle more memory (thx Fabric)

* Increase (?) / Specify memory for core tests

* Many attempts at fixing OOM

(cherry picked from commit bb013aa89b8457c4649e2546eef0aa94b9fc4020)

worldedit-core/build.gradle.kts

@@ -61,6 +61,10 @@ dependencies {
     implementation(kotlin("stdlib-jdk8", "1.3.61"))
 }
 
+tasks.named<Test>("test") {
+    maxHeapSize = "1G"
+}
+
 tasks.withType<JavaCompile>().configureEach {
     dependsOn(":worldedit-libs:build")
     options.compilerArgs.add("-Aarg.name.key.prefix=")