hg: lanai/lanai: 8232918: Unguarded use of displaySyncEnabled causes build to fail

[kevin.rushforth at oracle.com]

Changeset: 044a039f2a3f
Author:    kcr
Date:      2019-10-23 12:04 -0700
URL:       https://hg.openjdk.java.net/lanai/lanai/rev/044a039f2a3f

8232918: Unguarded use of displaySyncEnabled causes build to fail
Summary: Wrap displaySyncEnabled in @available check to avoid warning

! src/java.desktop/macosx/native/libawt_lwawt/java2d/metal/MTLLayer.m