compiler: move tests from vm/tests

These don't belong to VM as they compile some Go code and run it in a VM. One
may call them integration tests, but I prefer to attribute them to
compiler. Moving these tests into pkg/compiler also allows to properly count
the compiler coverage they add:

-ok     github.com/CityOfZion/neo-go/pkg/compiler       (cached)        coverage: 69.7% of statements
+ok     github.com/CityOfZion/neo-go/pkg/compiler       (cached)        coverage: 84.2% of statements

This change also fixes `contant` typo and removes fake packages exposed to the
public by moving foo/bar/foobar into the testdata directory.

pkg/compiler/assign_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"math/big"

pkg/compiler/binary_expr_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"math/big"

pkg/compiler/byte_conversion_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import "testing"
 

pkg/compiler/constant_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"math/big"

pkg/compiler/for_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"math/big"

pkg/compiler/function_call_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"math/big"

pkg/compiler/if_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"math/big"

pkg/compiler/import_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"math/big"
@@ -9,7 +9,7 @@ func TestImportFunction(t *testing.T) {
 	src := `
 		package somethingelse
 
-		import "github.com/CityOfZion/neo-go/pkg/vm/tests/foo"
+		import "github.com/CityOfZion/neo-go/pkg/compiler/testdata/foo"
 
 		func Main() int {
 			i := foo.NewBar()
@@ -23,7 +23,7 @@ func TestImportStruct(t *testing.T) {
 	src := `
 	 	package somethingwedontcareabout
 
-		import "github.com/CityOfZion/neo-go/pkg/vm/tests/bar"
+		import "github.com/CityOfZion/neo-go/pkg/compiler/testdata/bar"
 
 	 	func Main() int {
 			 b := bar.Bar{
@@ -39,7 +39,7 @@ func TestMultipleDirFileImport(t *testing.T) {
 	src := `
 		package hello
 
-		import "github.com/CityOfZion/neo-go/pkg/vm/tests/foobar"
+		import "github.com/CityOfZion/neo-go/pkg/compiler/testdata/foobar"
 
 		func Main() bool {
 			ok := foobar.OtherBool()

pkg/compiler/numeric_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"math/big"

pkg/compiler/slice_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"math/big"

pkg/compiler/struct_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"math/big"

pkg/compiler/syscall_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"testing"

pkg/compiler/type_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import "testing"
 

pkg/compiler/util_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"testing"

pkg/compiler/vm_test.go

@@ -1,4 +1,4 @@
-package vm_test
+package compiler_test
 
 import (
 	"fmt"