Shaman tests: ensure the temporary storage path is not a symlink

Shaman cannot handle cases where the storage path is a symlink (i.e. cases
where `filepath.EvalSymlinks(storagePath)` does not return `storagePath`).
This caused macOS devices to fail the unit tests, because macOS uses a
symlinked path for temporary files.

This commit changes the unit tests, to always use the real path instead of
the OS-provided symlink. This does *not* fix the actual issue in Shaman,
for that see T99965.

pkg/shaman/config/testing.go

@@ -25,6 +25,7 @@ package config
 import (
 	"io/ioutil"
 	"os"
+	"path/filepath"
 	"time"
 )
 
@@ -35,6 +36,11 @@ func CreateTestConfig() (conf Config, cleanup func()) {
 		panic(err)
 	}
 
+	tempDir, err = filepath.EvalSymlinks(tempDir)
+	if err != nil {
+		panic(err)
+	}
+
 	conf = Config{
 		TestTempDir: tempDir,
 		Enabled:     true,