treewide: parallel tests

Most tests already had no global state, however parallel was never enabled. This change enables it for all applicable tests.

Signed-off-by: Ophestra <cat@gensokyo.uk>

container/seccomp/proc.go

@@ -21,9 +21,7 @@ Methods of Encoder are not safe for concurrent use.
 
 An Encoder must not be copied after first use.
 */
-type Encoder struct {
-	*exporter
-}
+type Encoder struct{ *exporter }
 
 func (e *Encoder) Read(p []byte) (n int, err error) {
 	if err = e.prepare(); err != nil {