build: remove spark.driver.host workaround from Spark 4 build

The hostname binding hack is no longer needed now that the local
machine resolves its hostname to 127.0.0.1 via /etc/hosts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Tobias Kaymak

runners/spark/4/build.gradle

@@ -29,13 +29,9 @@ project.ext {
 // Load the main build script which contains all build logic.
 apply from: "$basePath/spark_runner.gradle"
 
-// Force Spark to bind to 127.0.0.1 so tests pass on machines where the hostname
-// doesn't resolve to a bindable address (e.g. mac.lan in macOS VPN environments).
 // Spark 4 always requires Java 17, so unconditionally add the --add-opens flags
 // required by Kryo and other libraries that use reflection on JDK internals.
 test {
-  systemProperty "spark.driver.host", "127.0.0.1"
-  systemProperty "spark.driver.bindAddress", "127.0.0.1"
   jvmArgs "--add-opens=java.base/sun.nio.ch=ALL-UNNAMED",
           "--add-opens=java.base/java.nio=ALL-UNNAMED",
           "--add-opens=java.base/java.util=ALL-UNNAMED",