Use mock JDK in compiler tests where full JDK is not needed

- move some of boxWithStdlib tests under fullJdk/ directory, where they will be
  compiled against the full JDK
- introduce FULL_JDK in-text directive for the reflection test as only 4 tests
  out of 654 needed the full JDK

compiler/testData/codegen/boxWithStdlib/fullJdk/native/simpleNative.kt

@@ -0,0 +1,17 @@
+package foo
+
+import kotlin.jvm.*
+
+class WithNative {
+    native fun foo()
+}
+
+fun box(): String {
+    try {
+        WithNative().foo()
+        return "Link error expected"
+    }
+    catch (e: java.lang.UnsatisfiedLinkError) {
+        return "OK"
+    }
+}