Re-enable WeakReferenceTest

Fixed by: eclipse-openj9/openj9#23312

Signed-off-by: Aditi Srinivas M Aditi.Srini@ibm.com

Author: Aditi Srinivas M

openjdk/excludes/ProblemList_openjdkvalhalla-openj9.txt

@@ -26,7 +26,6 @@ valhalla/valuetypes/NullRestrictedArraysTest.java https://github.com/eclipse-ope
 valhalla/valuetypes/NullRestrictedTest.java https://github.com/eclipse-openj9/openj9/issues/20404 generic-all
 valhalla/valuetypes/ValueObjectMethodsTest.java https://github.com/eclipse-openj9/openj9/issues/23172 generic-all
 valhalla/valuetypes/Reflection.java https://github.com/eclipse-openj9/openj9/issues/20404 generic-all
-valhalla/valuetypes/WeakReferenceTest.java https://github.com/eclipse-openj9/openj9/issues/20404 generic-all
 
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