Add x-pack filebeat and metricbeat stages for Windows and OSX (#18494)

Jenkins pipeline is not executing the tests on Windows and OSX for some x-pack
beats, so we cannot detect specific issues on these platforms, like the compilation
error in Windows solved by #18477, that was introduced after a green build.

Run x-pack Filebeat and Metricbeat builds and unit tests in Windows and OSX.

Jenkinsfile

@@ -162,6 +162,19 @@ pipeline {
             mageTarget("Filebeat oss Mac OS X", "filebeat", "build unitTest")
           }
         }
+        stage('Filebeat x-pack Mac OS X'){
+          agent { label 'macosx' }
+          options { skipDefaultCheckout() }
+          when {
+            beforeAgent true
+            expression {
+              return env.BUILD_XPACK_FILEBEAT != "false" && params.macosTest
+            }
+          }
+          steps {
+            mageTarget("Filebeat x-pack Mac OS X", "x-pack/filebeat", "build unitTest")
+          }
+        }
         stage('Filebeat Windows'){
           agent { label 'windows-immutable && windows-2019' }
           options { skipDefaultCheckout() }
@@ -175,6 +188,19 @@ pipeline {
             mageTargetWin("Filebeat oss Windows Unit test", "filebeat", "build unitTest")
           }
         }
+        stage('Filebeat x-pack Windows'){
+          agent { label 'windows-immutable && windows-2019' }
+          options { skipDefaultCheckout() }
+          when {
+            beforeAgent true
+            expression {
+              return env.BUILD_FILEBEAT_XPACK != "false" && params.windowsTest
+            }
+          }
+          steps {
+            mageTargetWin("Filebeat x-pack Windows", "x-pack/filebeat", "build unitTest")
+          }
+        }
         stage('Heartbeat'){
           agent { label 'ubuntu && immutable' }
           options { skipDefaultCheckout() }
@@ -419,6 +445,19 @@ pipeline {
             mageTarget("Metricbeat OSS Mac OS X", "metricbeat", "build unitTest")
           }
         }
+        stage('Metricbeat x-pack Mac OS X'){
+          agent { label 'macosx' }
+          options { skipDefaultCheckout() }
+          when {
+            beforeAgent true
+            expression {
+              return env.BUILD_METRICBEAT_XPACK != "false" && params.macosTest
+            }
+          }
+          steps {
+            mageTarget("Metricbeat x-pack Mac OS X", "x-pack/metricbeat", "build unitTest")
+          }
+        }
         stage('Metricbeat Windows'){
           agent { label 'windows-immutable && windows-2019' }
           options { skipDefaultCheckout() }
@@ -432,6 +471,19 @@ pipeline {
             mageTargetWin("Metricbeat Windows Unit test", "metricbeat", "build unitTest")
           }
         }
+        stage('Metricbeat x-pack Windows'){
+          agent { label 'windows-immutable && windows-2019' }
+          options { skipDefaultCheckout() }
+          when {
+            beforeAgent true
+            expression {
+              return env.BUILD_METRICBEAT_XPACK != "false" && params.windowsTest
+            }
+          }
+          steps {
+            mageTargetWin("Metricbeat x-pack Windows", "x-pack/metricbeat", "build unitTest")
+          }
+        }
         stage('Packetbeat'){
           agent { label 'ubuntu && immutable' }
           options { skipDefaultCheckout() }