8131126: Set update release to 8u66 and keep default jprt release as 8u60 on jdk8u repos

Reviewed-by: dholmes, tbell, mikael

make/jprt.properties

@@ -29,8 +29,8 @@
 #
 
 # The current release name
-my.jdk.update.version=60
-jprt.tools.default.release=jdk8u${my.jdk.update.version}
+my.jdk.update.version=66
+jprt.tools.default.release=jdk8u60
 
 # Check if this is the equivalent of a hotspot push job
 # Interpret -testset hotspot to mean exactly that