disable on mac

Signed-off-by: Sally MacFarlane <[email protected]>

ethereum/eth/src/test/java/org/hyperledger/besu/ethereum/eth/transactions/PendingTransactionEstimatedMemorySizeTest.java

@@ -96,7 +96,7 @@
  * then complete the writing of the test that will verify the current amount of memory used by that
  * class.
  */
-@EnabledOnOs({OS.LINUX, OS.MAC})
+@EnabledOnOs({OS.LINUX})
 public class PendingTransactionEstimatedMemorySizeTest extends BaseTransactionPoolTest {
   /**
    * Classes that represent constant instances, across all pending transaction types, and are