Enable IdentityReflectionTest.java (#7128)

Enable IdentityReflectionTest.java
Fixed by: eclipse-openj9/openj9#23945

Co-authored-by: Aditi Srinivas M <Aditi.Srini@ibm.com>

Author: AditiS11

openjdk/excludes/ProblemList_openjdkvalhalla-openj9.txt

@@ -19,7 +19,6 @@
 # jdk_valhalla_j9 - valhalla
 
 ############################################################################
-valhalla/valuetypes/IdentityReflectionTest.java https://github.com/eclipse-openj9/openj9/issues/20404 generic-all
 valhalla/valuetypes/MethodHandleTest.java https://github.com/eclipse-openj9/openj9/issues/22648 generic-all
 valhalla/valuetypes/ValueObjectMethodsTest.java https://github.com/eclipse-openj9/openj9/issues/15768 generic-all
 valhalla/valuetypes/RecursiveValueClass.java https://github.com/eclipse-openj9/openj9/issues/15768 generic-all