Fix XUnitLogChecker detection for local test runs (#96638)

* Fix XUnitLogChecker detection for local test runs

* DO NOT MERGE: Temporary crash to confirm XUnitLogChecker still works as expected in the CI.

* Revert "DO NOT MERGE: Temporary crash to confirm XUnitLogChecker still works as expected in the CI."

This reverts commit 9e01406.

* Skip in Unix too

eng/testing/RunnerTemplate.cmd

@@ -98,6 +98,9 @@ if %_exit_code%==1 (
   )
 )
 
+if "%HELIX_CORRELATION_PAYLOAD%"=="" (
+  GOTO SKIP_XUNITLOGCHECKER
+)
 if NOT "%__IsXUnitLogCheckerSupported%"=="1" (
   echo XUnitLogChecker not supported for this test case. Skipping.
   GOTO SKIP_XUNITLOGCHECKER

eng/testing/RunnerTemplate.sh

@@ -233,7 +233,9 @@ if [ -n "$HELIX_WORKITEM_PAYLOAD" ]; then
 
 fi
 
-if [[ -z "$__IsXUnitLogCheckerSupported" ]]; then
+if [[ -z "$HELIX_CORRELATION_PAYLOAD" ]]; then
+  : # Skip XUnitLogChecker execution
+elif [[ -z "$__IsXUnitLogCheckerSupported" ]]; then
   echo "The '__IsXUnitLogCheckerSupported' env var is not set."
 elif [[ "$__IsXUnitLogCheckerSupported" != "1" ]]; then
   echo "XUnitLogChecker not supported for this test case. Skipping."