This commit reverts the changes made in 7bc44a90 so that developers who
do not use the Gradle daemon are not adversely affected by the explicit
JVM args that were introduced in that commit.

Developers who wish to run the build against JDK 9 with the Gradle
daemon can add the following to the gradle.properties file in their
'gradle user home' directory (e.g., ~/.gradle/gradle.properties):

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

See also: https://issues.gradle.org/browse/GRADLE-3256

Issue: SPR-12549

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

This reverts commit 4788875a.