Fixes #283 : ensure test.Assert compile cache handles different objects of same type

[gbotrel]

additionally, adds a bit of parallelism in the Assert object, after the compile phase.
Not extremely efficient since most algorithms after the compile phase are already parallel.

[ivokub]

Suggested edit:

diff --git a/frontend/compile.go b/frontend/compile.go
index c6d1140b..a0f98c19 100644
--- a/frontend/compile.go
+++ b/frontend/compile.go
@@ -81,7 +81,6 @@ func parseCircuit(builder Builder, circuit Circuit) (err error) {
 	// leafs are Constraints that need to be initialized in the context of compiling a circuit
 	var handler schema.LeafHandler = func(visibility schema.Visibility, name string, tInput reflect.Value) error {
 		if tInput.CanSet() {
-			// log.Trace().Str("name", name).Str("visibility", visibility.String()).Msg("init input wire")
 			switch visibility {
 			case schema.Secret:
 				tInput.Set(reflect.ValueOf(builder.AddSecretVariable(name)))
diff --git a/test/assert.go b/test/assert.go
index b3556491..ce390b13 100644
--- a/test/assert.go
+++ b/test/assert.go
@@ -443,7 +443,7 @@ func (assert *Assert) compile(circuit frontend.Circuit, curveID ecc.ID, backendI
 		return nil, ErrCompilationNotDeterministic
 	}
 
-	// // add the compiled circuit to the cache
+	// add the compiled circuit to the cache
 	assert.compiled[key] = ccs
 
 	return ccs, nil

[ivokub]

Looks good.