Adapt to compile and runtime Java home distinction

We now separate the compiler Java home from the time runtime Java home
(the one that is used to compile class files versus the one that is used
to run tests). This commit adapts x-pack-elasticsearch to this change.

Relates elastic/x-pack-elasticsearch#3477

Original commit: elastic/x-pack-elasticsearch@bdb096e21c

plugin/build.gradle

@@ -224,7 +224,7 @@ task createNodeKeyStore(type: LoggedExec) {
       delete nodeKeystore
     }
   }
-  executable = new File(project.javaHome, 'bin/keytool')
+  executable = new File(project.runtimeJavaHome, 'bin/keytool')
   standardInput = new ByteArrayInputStream('FirstName LastName\nUnit\nOrganization\nCity\nState\nNL\nyes\n\n'.getBytes('UTF-8'))
   args '-genkey',
           '-alias', 'test-node',

plugin/bwc-snapshot-dummy-projects/build.gradle

@@ -186,25 +186,31 @@ subprojects {
     task buildBwcVersion(type: Exec) {
       dependsOn checkoutXPackBwcBranch, checkoutElasticsearchBwcBranch, writeElasticsearchBuildMetadata, writeXPackBuildMetadata
       workingDir = xpackCheckoutDir
+      if (project.rootProject.ext.runtimeJavaVersion == JavaVersion.VERSION_1_8 && ["5.6", "6.0", "6.1"].contains(bwcBranch)) {
+        /*
+         * If runtime Java home is set to JDK 8 and we are building branches that are officially built with JDK 8, push this to JAVA_HOME for
+         * these builds.
+         */
+        environment('JAVA_HOME', System.getenv('RUNTIME_JAVA_HOME'))
+      }
       if (Os.isFamily(Os.FAMILY_WINDOWS)) {
         executable 'cmd'
         args '/C', 'call', new File(xpackCheckoutDir, 'gradlew').toString()
       } else {
-        executable = new File(xpackCheckoutDir, 'gradlew').toString()
+        executable new File(xpackCheckoutDir, 'gradlew').toString()
       }
-      final ArrayList<String> commandLineArgs = [":x-pack-elasticsearch:plugin:assemble", "-Dbuild.snapshot=${System.getProperty('build.snapshot') ?: 'true'}"]
+      args ":x-pack-elasticsearch:plugin:assemble", "-Dbuild.snapshot=${System.getProperty('build.snapshot') ?: 'true'}"
       final LogLevel logLevel = gradle.startParameter.logLevel
       if ([LogLevel.QUIET, LogLevel.WARN, LogLevel.INFO, LogLevel.DEBUG].contains(logLevel)) {
-        commandLineArgs << "--${logLevel.name().toLowerCase(Locale.ENGLISH)}"
+        args "--${logLevel.name().toLowerCase(Locale.ENGLISH)}"
       }
       final String showStacktraceName = gradle.startParameter.showStacktrace.name()
       assert ["INTERNAL_EXCEPTIONS", "ALWAYS", "ALWAYS_FULL"].contains(showStacktraceName)
       if (showStacktraceName.equals("ALWAYS")) {
-        commandLineArgs << "--stacktrace"
+        args "--stacktrace"
       } else if (showStacktraceName.equals("ALWAYS_FULL")) {
-        commandLineArgs << "--full-stacktrace"
+        args "--full-stacktrace"
       }
-      args commandLineArgs
     }
 
     artifacts {

qa/smoke-test-plugins-ssl/build.gradle

@@ -42,7 +42,7 @@ task createNodeKeyStore(type: LoggedExec) {
       delete nodeKeystore
     }
   }
-  executable = new File(project.javaHome, 'bin/keytool')
+  executable = new File(project.runtimeJavaHome, 'bin/keytool')
   standardInput = new ByteArrayInputStream('FirstName LastName\nUnit\nOrganization\nCity\nState\nNL\nyes\n\n'.getBytes('UTF-8'))
   args '-genkey',
           '-alias', 'test-node',
@@ -67,7 +67,7 @@ task createClientKeyStore(type: LoggedExec) {
       delete clientKeyStore
     }
   }
-  executable = new File(project.javaHome, 'bin/keytool')
+  executable = new File(project.runtimeJavaHome, 'bin/keytool')
   standardInput = new ByteArrayInputStream('FirstName LastName\nUnit\nOrganization\nCity\nState\nNL\nyes\n\n'.getBytes('UTF-8'))
   args '-genkey',
           '-alias', 'test-client',
@@ -92,7 +92,7 @@ task exportNodeCertificate(type: LoggedExec) {
       delete nodeCertificate
     }
   }
-  executable = new File(project.javaHome, 'bin/keytool')
+  executable = new File(project.runtimeJavaHome, 'bin/keytool')
   args '-export',
           '-alias', 'test-node',
           '-keystore', nodeKeystore,
@@ -103,7 +103,7 @@ task exportNodeCertificate(type: LoggedExec) {
 // Import the node certificate in the client's keystore
 task importNodeCertificateInClientKeyStore(type: LoggedExec) {
   dependsOn exportNodeCertificate
-  executable = new File(project.javaHome, 'bin/keytool')
+  executable = new File(project.runtimeJavaHome, 'bin/keytool')
   args '-import',
           '-alias', 'test-node',
           '-keystore', clientKeyStore,
@@ -123,7 +123,7 @@ task exportClientCertificate(type: LoggedExec) {
       delete clientCertificate
     }
   }
-  executable = new File(project.javaHome, 'bin/keytool')
+  executable = new File(project.runtimeJavaHome, 'bin/keytool')
   args '-export',
           '-alias', 'test-client',
           '-keystore', clientKeyStore,
@@ -134,7 +134,7 @@ task exportClientCertificate(type: LoggedExec) {
 // Import the client certificate in the node's keystore
 task importClientCertificateInNodeKeyStore(type: LoggedExec) {
   dependsOn exportClientCertificate
-  executable = new File(project.javaHome, 'bin/keytool')
+  executable = new File(project.runtimeJavaHome, 'bin/keytool')
   args '-import',
           '-alias', 'test-client',
           '-keystore', nodeKeystore,