[CT] Fix isolate_telemetry on windows

Bug: skia:11884
Change-Id: I31072afec5e61f6b86d0cbac423642c194294b55
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/398697
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Ravi Mistry <rmistry@google.com>
diff --git a/ct/go/worker_scripts/isolate_telemetry/main.go b/ct/go/worker_scripts/isolate_telemetry/main.go
index 30d4f8b..21ffeb0 100644
--- a/ct/go/worker_scripts/isolate_telemetry/main.go
+++ b/ct/go/worker_scripts/isolate_telemetry/main.go
@@ -80,7 +80,7 @@
 	}
 
 	buildOutDir := filepath.Join(util.ChromiumSrcDir, util.TELEMETRY_ISOLATES_OUT_DIR)
-	isolateFile := filepath.Join(buildOutDir, fmt.Sprintf("%s.isolate", util.TELEMETRY_ISOLATES_TARGET))
+	isolateFile := fmt.Sprintf("%s.isolate", util.TELEMETRY_ISOLATES_TARGET)
 
 	// Isolate telemetry artifacts.
 	hash, err := isolate.Upload(ctx, rbe.InstanceChromeSwarming, buildOutDir, isolateFile)