graphics: ignore/reduce spurious vsync in VTS

Bug: 62802718
Test: VTS
Change-Id: I1ed73e0b2f14414f540865a96e6bd5ac1599fbf3
diff --git a/graphics/composer/2.1/vts/functional/VtsHalGraphicsComposerTestUtils.cpp b/graphics/composer/2.1/vts/functional/VtsHalGraphicsComposerTestUtils.cpp
index 4e65a95..c66cdd0 100644
--- a/graphics/composer/2.1/vts/functional/VtsHalGraphicsComposerTestUtils.cpp
+++ b/graphics/composer/2.1/vts/functional/VtsHalGraphicsComposerTestUtils.cpp
@@ -297,6 +297,11 @@
                                            : IComposerClient::Vsync::DISABLE;
   Error error = mClient->setVsyncEnabled(display, vsync);
   ASSERT_EQ(Error::NONE, error) << "failed to set vsync mode";
+
+  // give the hwbinder thread some time to handle any pending vsync callback
+  if (!enabled) {
+      usleep(5 * 1000);
+  }
 }
 
 void ComposerClient::execute(TestCommandReader* reader,