metatransaction context refactor (#730)

fvm/fvm.go

@@ -87,12 +87,14 @@ func (vm *VirtualMachine) GetAccount(ctx Context, address flow.Address, v state.
 //
 // Errors that occur in a meta transaction are propagated as a single error that can be
 // captured by the Cadence runtime and eventually disambiguated by the parent context.
-func (vm *VirtualMachine) invokeMetaTransaction(ctx Context, tx *TransactionProcedure, sth *state.StateHolder, programs *programs.Programs) (errors.Error, error) {
+func (vm *VirtualMachine) invokeMetaTransaction(parentCtx Context, tx *TransactionProcedure, sth *state.StateHolder, programs *programs.Programs) (errors.Error, error) {
 	invocator := NewTransactionInvocator(zerolog.Nop())
 
 	// do not deduct fees or check storage in meta transactions
-	ctx.TransactionFeesEnabled = false
-	ctx.LimitAccountStorage = false
+	ctx := NewContextFromParent(parentCtx,
+		WithAccountStorageLimit(false),
+		WithTransactionFeesEnabled(false),
+	)
 
 	err := invocator.Process(vm, &ctx, tx, sth, programs)
 	txErr, fatalErr := errors.SplitErrorTypes(err)