Add correct test coverage branch detection

ci/Jenkinsfile_utils.groovy

@@ -75,8 +75,25 @@ echo ${libs} | sed -e 's/,/ /g' | xargs md5sum
 }
 
 def publish_test_coverage() {
+    // CodeCovs auto detection has trouble with our CIs PR validation due the merging strategy
+    def codecovArgs = ""
+    if (env.CHANGE_ID != '') {
+      // PR execution
+      // Take the previous commit because of our PR merge strategy that adds a temporary commit for CI
+      GIT_COMMIT_HASH = sh (script: "git rev-parse @~", returnStdout: true)
+      codecovArgs += "-B ${env.CHANGE_TARGET} " +
+        "-C ${GIT_COMMIT_HASH} " +
+        "-P ${env.CHANGE_ID} "
+    } else {
+      // Branch execution
+      GIT_COMMIT_HASH = sh (script: "git rev-parse @", returnStdout: true)
+      codecovArgs += "-B ${env.BRANCH_NAME} " +
+        "-C ${GIT_COMMIT_HASH} "
+    }
+
+    // To make sure we never fail because test coverage reporting is not available
     // Fall back to our own copy of the bash helper if it failed to download the public version
-    sh '(curl --retry 10 -s https://codecov.io/bash | bash -s -) || (curl --retry 10 -s https://s3-us-west-2.amazonaws.com/mxnet-ci-prod-slave-data/codecov-bash.txt | bash -s -)'
+    sh "(curl --retry 10 -s https://codecov.io/bash | bash -s - ${codecovArgs}) || (curl --retry 10 -s https://s3-us-west-2.amazonaws.com/mxnet-ci-prod-slave-data/codecov-bash.txt | bash -s - ${codecovArgs}) || true"
 }
 
 def collect_test_results_unix(original_file_name, new_file_name) {