Move some tests from boxWithStdlib/ to box/

Move those tests which do not require neither stdlib nor reflect

compiler/testData/codegen/box/fullJdk/charBuffer.kt

@@ -0,0 +1,11 @@
+// FULL_JDK
+
+import java.nio.CharBuffer
+
+fun box(): String {
+    val cb = CharBuffer.wrap("OK")
+    cb.position(1)
+    val o = cb[0]
+    val k = (cb as CharSequence).get(0)
+    return o.toString() + k
+}