compiler: emit integers correctly

A while ago VM serialization format for Integer items was changed
but compiler continued to emit Integers in old format.
This commit changes compiler behaviour to be compatible with VM.

pkg/compiler/emit.go

@@ -7,7 +7,7 @@ import (
 	"math/big"
 
 	"github.com/CityOfZion/neo-go/pkg/io"
-	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/CityOfZion/neo-go/pkg/vm"
 	"github.com/CityOfZion/neo-go/pkg/vm/opcode"
 )
 
@@ -47,7 +47,7 @@ func emitInt(w *io.BinWriter, i int64) {
 	}
 
 	bInt := big.NewInt(i)
-	val := util.ArrayReverse(bInt.Bytes())
+	val := vm.IntToBytes(bInt)
 	emitBytes(w, val)
 }
 

pkg/compiler/limit_test.go

@@ -0,0 +1,26 @@
+package compiler_test
+
+import (
+	"bytes"
+	"fmt"
+	"math/big"
+	"testing"
+)
+
+// Test for #605, #623.
+// Codegen should emit integers in proper format.
+func TestManyVariables(t *testing.T) {
+	// any number with MSB=1 is suitable
+	// 155 was in the contract where this bug was first found.
+	const count = 155
+
+	buf := bytes.NewBufferString("package main\n")
+	for i := 0; i < count; i++ {
+		buf.WriteString(fmt.Sprintf("var a%d = %d\n", i, i))
+	}
+	buf.WriteString("func Main() int {\nreturn 7\n}\n")
+
+	src := buf.String()
+
+	eval(t, src, big.NewInt(7))
+}