8355492: MissedOptCastII is missing UnlockDiagnosticVMOptions flag

Reviewed-by: rcastanedalo, chagedorn, thartmann

Author: marc-chevalier

test/hotspot/jtreg/compiler/c2/gvn/MissedOptCastII.java

@@ -32,6 +32,7 @@
  *           -XX:CompileCommand=compileonly,MissedOptCastII::*
  *           -XX:-TieredCompilation -Xcomp
  *           -XX:+IgnoreUnrecognizedVMOptions
+ *           -XX:+UnlockDiagnosticVMOptions
  *           -XX:+StressIGVN -XX:VerifyIterativeGVN=10
  *           MissedOptCastII
  */