compiler: simplify convert.To* processing

With inlining there is no need for special logic in compiler.

pkg/compiler/analysis.go

@@ -327,6 +327,5 @@ func canInline(s string) bool {
 		return false
 	}
 	return !strings.HasPrefix(s[len(interopPrefix):], "/neogointernal") &&
-		!strings.HasPrefix(s[len(interopPrefix):], "/util") &&
-		!strings.HasPrefix(s[len(interopPrefix):], "/convert")
+		!strings.HasPrefix(s[len(interopPrefix):], "/util")
 }

pkg/compiler/codegen.go

@@ -1708,15 +1708,6 @@ func (c *codegen) convertBuiltin(expr *ast.CallExpr) {
 		c.emitStoreByIndex(varGlobal, c.exceptionIndex)
 	case "delete":
 		emit.Opcodes(c.prog.BinWriter, opcode.REMOVE)
-	case "ToInteger", "ToByteArray", "ToBool":
-		typ := stackitem.IntegerT
-		switch name {
-		case "ToByteArray":
-			typ = stackitem.ByteArrayT
-		case "ToBool":
-			typ = stackitem.BooleanT
-		}
-		c.emitConvert(typ)
 	case "Remove":
 		if !isCompoundSlice(c.typeOf(expr.Args[0])) {
 			c.prog.Err = errors.New("`Remove` supports only non-byte slices")

pkg/interop/convert/convert.go

@@ -3,15 +3,15 @@ package convert
 
 // ToInteger converts it's argument to an Integer.
 func ToInteger(v interface{}) int64 {
-	return 0
+	return v.(int64)
 }
 
 // ToByteArray converts it's argument to a ByteArray.
 func ToByteArray(v interface{}) []byte {
-	return nil
+	return v.([]byte)
 }
 
 // ToBool converts it's argument to a Boolean.
 func ToBool(v interface{}) bool {
-	return false
+	return v.(bool)
 }