compiler: add contract example to measure coverage

After `cd pkg/compiler` I ran test using command `go test -run '^TestSome$' -coverprofile=./contract/cover.out -cover`
received file `./contract/cover.out` ran following command `go test -run'^TestSome$' -coverprofile=./contract/cover.out -cover`
and got this result:
`
neo-go/pkg/compiler/contract/contract.go:3: MyEven 0.0%
total:                                                                          (statements)    0.0%
`
although in `TestSome` case was tested when the number is even

Signed-off-by: Tural Devrishev <tural@nspcc.ru>

Author: Tural Devrishev

pkg/compiler/contract/contract.go

@@ -0,0 +1,8 @@
+package contract
+
+func MyEven(n int) bool {
+	if n%2 == 0 { //nolint: gosimple
+		return true
+	}
+	return false
+}

pkg/compiler/contract/contract.yml

@@ -0,0 +1 @@
+name: "contract example"

pkg/compiler/contract/cover.out

@@ -0,0 +1,3 @@
+mode: set
+/home/turalchik/repositories/neo-go/pkg/compiler/contract/contract.go:5.3,5.14 1 0
+/home/turalchik/repositories/neo-go/pkg/compiler/contract/contract.go:7.2,7.14 1 0

pkg/compiler/interop_test.go

@@ -799,3 +799,14 @@ func Main() int {
 
 	c.Invoke(t, big.NewInt(3), "main")
 }
+
+func TestSome(t *testing.T) {
+	bc, acc := chain.NewSingle(t)
+	e := neotest.NewExecutor(t, bc, acc, acc)
+
+	ctr := neotest.CompileFile(t, e.CommitteeHash, "./contract/contract.go", "./contract/contract.yml")
+	e.DeployContract(t, ctr, nil)
+	c := e.CommitteeInvoker(ctr.Hash)
+
+	c.Invoke(t, true, "myEven", 0)
+}