Set Gradle Daemon JVM args compatible with JDK 9

This commit adds the following to gradle.properties in order to execute
the Gradle daemon on JDK 9, since Gradle's DaemonParameters
automatically sets the MaxPermSize JVM argument, which is no longer
supported on JDK 9.

org.gradle.jvmargs=-XX:MaxMetaspaceSize=1024m -Xmx1024m

Issue: SPR-12549

gradle.properties

@@ -1 +1,6 @@
 version=4.2.0.BUILD-SNAPSHOT
+
+# The following is necessary for running the Gradle daemon on JDK 9, since
+# Gradle's DaemonParameters automatically sets the MaxPermSize JVM argument,
+# which is no longer supported on JDK 9.
+org.gradle.jvmargs=-XX:MaxMetaspaceSize=1024m -Xmx1024m