[IR BE] Fix capturing of var-locals inside class/field initializers

compiler/testData/codegen/box/callableReference/bound/captureVarInPropertyInit.kt

@@ -0,0 +1,18 @@
+
+fun bar(b: ()-> Unit) { b() }
+
+class C() {
+    val p: Int = run {
+        var v = 10
+        bar() {
+            v = 20
+        }
+        v + 1
+    }
+}
+
+fun box(): String {
+    val c = C()
+    if (c.p != 21) return "fail ${c.p}"
+    return "OK"
+}