Disable tests causing random failures with Enso and read barriers.

The new implementation of java.lang.reflect.Proxy (in
libcore/ojluni/src/main/java/java/lang/reflect/Proxy.java)
uses weak references (in getProxyClass0).  Two ART run-tests
(044-proxy and 005-annotations) rely on precise proxy
class names being outputted, but because weak references may
not be collected on time, there is sometimes a discrepancy
between expected and actual results in those tests.  This
issue seems to be triggereed more frequently with the
implementation of read barriers in the compiler, which
relies on a slow path always calling a runtime entry point.

This problem did not happen before Enso, as the old
implementation of getProxyClass
(libcore/libart/src/main/java/java/lang/reflect/Proxy.java)
did not use weak references (in getProxyClass).

Temporarily disable tests 044-proxy and 005-annotations to
make the art-read-barrier build turn green again.

Bug: 25838574
Change-Id: Ibfcdeb41572580c0e22b7688879e4b8b1cdb68e1