slack-vitess-r14.0.5: use dedicated larger runner

.github/workflows/cluster_endtoend_ers_prs_newfeatures_heavy.yml

@@ -9,7 +9,8 @@ concurrency:
 jobs:
   build:
     name: Run endtoend tests on Cluster (ers_prs_newfeatures_heavy)
-    runs-on: ubuntu-20.04
+    runs-on:
+      group: vitess-ubuntu20
 
     steps:
     - name: Check if workflow needs to be skipped

go/test/endtoend/reparent/newfeaturetest/reparent_test.go

@@ -19,6 +19,7 @@ package newfeaturetest
 import (
 	"context"
 	"strconv"
+	"strings"
 	"testing"
 	"time"
 
@@ -205,7 +206,7 @@ func TestFullStatus(t *testing.T) {
 
 // fileNameFromPosition gets the file name from the position
 func fileNameFromPosition(pos string) string {
-	return pos[0 : len(pos)-4]
+	return strings.Split(pos, ":")[0]
 }
 
 // rowNumberFromPosition gets the row number from the position