[ML] Upgrade Gradle to v5.0 (elastic#325)

Needs to be merged before elastic/elasticsearch#34263 to
prevent builds with ml-cpp in elasticsearch-extra from
failing.

Defining a custom wrapper task was incompatible with
Gradle 5, so this is replaced with a modification to the
built in wrapper task.

The Gradle Wrapper is also upgraded to the latest version.

build.gradle

@@ -188,16 +188,15 @@ task build(dependsOn: [check, assemble]) {
   description = 'Assemble and test the C++ part of Machine Learning'
 }
 
-task wrapper(type: Wrapper) {
-    distributionType = DistributionType.ALL
-
+wrapper {
+    distributionType = 'ALL'
     doLast {
         final DistributionLocator locator = new DistributionLocator()
         final GradleVersion version = GradleVersion.version(wrapper.gradleVersion)
         final URI distributionUri = locator.getDistributionFor(version, wrapper.distributionType.name().toLowerCase(Locale.ENGLISH))
         final URI sha256Uri = new URI(distributionUri.toString() + ".sha256")
         final String sha256Sum = new String(sha256Uri.toURL().bytes)
         wrapper.getPropertiesFile() << "distributionSha256Sum=${sha256Sum}\n"
+        println "Added checksum to wrapper properties"
     }
 }
-

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.10-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.0-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionSha256Sum=fc049dcbcb245d5892bebae143bd515a78f6a5a93cec99d489b312dc0ce4aad9
+distributionSha256Sum=17847c8e12b2bcfce26a79f425f082c31d4ded822f99a66127eee2d96bf18216

gradlew

@@ -28,7 +28,7 @@ APP_NAME="Gradle"
 APP_BASE_NAME=`basename "$0"`
 
 # Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS=""
+DEFAULT_JVM_OPTS='"-Xmx64m"'
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD="maximum"

gradlew.bat

@@ -14,7 +14,7 @@ set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=
+set DEFAULT_JVM_OPTS="-Xmx64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome

upload.gradle

@@ -91,16 +91,3 @@ task uberUpload(type: UploadS3Task, dependsOn: buildUberZip) {
   description = 'Upload C++ uber zip to S3 Bucket'
 }
 
-task wrapper(type: Wrapper) {
-    distributionType = DistributionType.ALL
-
-    doLast {
-        final DistributionLocator locator = new DistributionLocator()
-        final GradleVersion version = GradleVersion.version(wrapper.gradleVersion)
-        final URI distributionUri = locator.getDistributionFor(version, wrapper.distributionType.name().toLowerCase(Locale.ENGLISH))
-        final URI sha256Uri = new URI(distributionUri.toString() + ".sha256")
-        final String sha256Sum = new String(sha256Uri.toURL().bytes)
-        wrapper.getPropertiesFile() << "distributionSha256Sum=${sha256Sum}\n"
-    }
-}
-