compiler: count auxiliary locals introduced by inlining

During initialization of globals no function scope is present thus
locals number is not saved anywere. Save it in `codegen` directly.

pkg/compiler/analysis.go

@@ -98,6 +98,10 @@ func (c *codegen) traverseGlobals() bool {
 		c.scope = nil
 	})
 
+	if c.globalInlineCount > maxCnt {
+		maxCnt = c.globalInlineCount
+	}
+
 	// Here we remove `INITSLOT` if no code was emitted for `init` function.
 	// Note that the `INITSSLOT` must stay in place.
 	hasNoInit := initOffset+3 == c.prog.Len()

pkg/compiler/codegen.go

@@ -61,6 +61,9 @@ type codegen struct {
 	// inlineLabelOffsets contains size of labelList at the start of inline call processing.
 	// For such calls we need to drop only newly created part of stack.
 	inlineLabelOffsets []int
+	// globalInlineCount contains amount of auxiliary variables introduced by
+	// function inlining during global variables initialization.
+	globalInlineCount int
 
 	// A label for the for-loop being currently visited.
 	currentFor string

pkg/compiler/inline.go

@@ -32,7 +32,12 @@ func (c *codegen) inlineCall(f *funcScope, n *ast.CallExpr) {
 	if c.scope == nil {
 		c.scope = &funcScope{}
 		c.scope.vars.newScope()
-		defer func() { c.scope = nil }()
+		defer func() {
+			if cnt := c.scope.vars.localsCnt; cnt > c.globalInlineCount {
+				c.globalInlineCount = cnt
+			}
+			c.scope = nil
+		}()
 	}
 
 	// Arguments need to be walked with the current scope,

pkg/compiler/syscall_test.go

@@ -191,8 +191,6 @@ func TestNotify(t *testing.T) {
 }
 
 func TestSyscallInGlobalInit(t *testing.T) {
-	// FIXME(fyrchik): count auxiliary inline locals for INITSLOT in global context
-	t.Skip()
 	src := `package foo
 		import "github.com/nspcc-dev/neo-go/pkg/interop/runtime"
 		var a = runtime.CheckWitness([]byte("5T"))