add JVM flags to work around possible freezes

These flags work around freezes described by http://v.io/i/567. Whether or not
these are actually causing the freezes in Swing/Vanadium binaries is not yet
known, but these flags can't hurt.

Change-Id: I132eb1bfecc0912d5447f76e4c05eef2eaf9a62e
diff --git a/projects/syncslidepresenter/build.gradle b/projects/syncslidepresenter/build.gradle
index 7e8a051..258e6da 100644
--- a/projects/syncslidepresenter/build.gradle
+++ b/projects/syncslidepresenter/build.gradle
@@ -14,6 +14,9 @@
 }
 
 mainClassName = "io.v.syncslidepresenter.Main"
+// Work around potential freezes in Java/Vanadium binaries
+// described by http://v.io/i/567.
+applicationDefaultJvmArgs = ['-XX:+UnlockDiagnosticVMOptions', '-XX:-LogEvents']
 
 repositories {
     mavenCentral()