Use hard-coded workpace for windows builds to avoid path length issues

Author: mark-vieira

.ci/jobs.t/elastic+elasticsearch+pull-request+part-1-windows.yml

@@ -4,6 +4,7 @@
     display-name: "elastic / elasticsearch # %BRANCH% - pull request part-1 windows"
     description: "Testing of Elasticsearch pull requests - part-1 windows"
     node: "windows-immutable"
+    workspace: "C:\\Users\\jenkins\\workspace\\pr-part-1\\${BUILD_NUMBER}"
     scm:
       - git:
           refspec: "+refs/pull/${ghprbPullId}/*:refs/remotes/origin/pr/${ghprbPullId}/*"

.ci/jobs.t/elastic+elasticsearch+pull-request+part-2-windows.yml

@@ -4,6 +4,7 @@
     display-name: "elastic / elasticsearch # %BRANCH% - pull request part-2 windows"
     description: "Testing of Elasticsearch pull requests - part-2 windows"
     node: "windows-immutable"
+    workspace: "C:\\Users\\jenkins\\workspace\\pr-part-2\\${BUILD_NUMBER}"
     scm:
       - git:
           refspec: "+refs/pull/${ghprbPullId}/*:refs/remotes/origin/pr/${ghprbPullId}/*"