Freeze top-level val. (#1906)

backend.native/tests/runtime/memory/escape2.kt

@@ -19,6 +19,7 @@ fun bar(b: B) {
     foo(c)
 }
 
+@ThreadLocal
 val global = B()
 
 @Test fun runTest() {

backend.native/tests/runtime/workers/freeze_stress.kt

@@ -68,6 +68,7 @@ class Graph(val nodes: List<Node>, val roots: List<Node>)
 fun min(x: Int, y: Int) = if (x < y) x else y
 fun max(x: Int, y: Int) = if (x > y) x else y
 
+@ThreadLocal
 val random = Random(42)
 
 fun generate(condensationSize: Int, branchingFactor: Int, swellingFactor: Int): Graph {