8239503: FieldLayout/OldLayoutCheck.java fails due to "RuntimeExcepti…

…on: Misplaced int field: expected 24 to equal 12"

Don't run the test with ZGC.

Reviewed-by: dcubed, coleenp, dholmes

test/hotspot/jtreg/runtime/FieldLayout/OldLayoutCheck.java

@@ -28,7 +28,7 @@
  * @library /test/lib
  * @modules java.base/jdk.internal.misc
  *          java.management
- * @requires vm.bits == "64"
+ * @requires vm.bits == "64" & vm.gc != "Z"
  * @run main/othervm -XX:+UseCompressedClassPointers -XX:-UseEmptySlotsInSupers OldLayoutCheck
  */