Backport of 6724345 "incorrect method resolution for enum classes entered as source files" to OpenJDK 6

[Joseph D. Darcy]

Hello.

Since it causing at least occasional problems and is a very small fix, 
I've decided to backport the fix for

6724345 "incorrect method resolution for enum classes entered as source 
files"
http://hg.openjdk.java.net/jdk7/tl/langtools/rev/ac6ce899d007

from JDK 7 to OpenJDK 6 b19.  The patch applies cleanly and Jon has 
approved the fix going back.

-Joe

[1] 
http://mail.openjdk.java.net/pipermail/compiler-dev/2010-February/001887.html