fix all the bugs

So there I was, planning to just fix one little bug: Thread.holdsLock
and Thread.yield were missing for the Android class library.  Easy
enough, right?  So, I added a test, got it passing, and figured I'd go
ahead and run ci.sh with all three class libraries.  Big mistake.

Here's the stuff I found:

 * minor inconsistency in README.md about OpenSSL version

 * untested, broken Class.getEnclosingMethod (reported by Josh)

 * JNI test failed for tails=true Android build

 * Runtime.nativeExit missing for Android build

 * obsolete assertion in CallEvent broke tails=true Android build

 * obsolete superclass field offset padding broke bootimage=true Android build

 * runtime annotation parsing broke bootimage=true Android build
   (because we couldn't modify Addendum.annotationTable for classes in
   the heap image)

 * ci.sh tried building with both android=... and openjdk=..., which
   the makefile rightfully balked at

Sorry this is all in a single commit; I didn't expect so many
unrelated issues, and I'm too lazy to break them apart.

test/Reflection.java

@@ -255,6 +255,11 @@ public class Reflection {
 
     expect(Baz.class.getField("foo").getAnnotation(Ann.class) == null);
     expect(Baz.class.getField("foo").getAnnotations().length == 0);
+
+    expect(new Runnable() { public void run() { } }.getClass()
+           .getEnclosingMethod().equals
+           (Reflection.class.getMethod
+            ("main", new Class[] { String[].class })));
   }
 
   protected static class Baz {