Bug 1589207 - Suppress two leaks in WebPlatform tests. r=mccr8

Differential Revision: https://phabricator.services.mozilla.com/D49640

--HG--
extra : moz-landing-system : lando

testing/web-platform/meta/pointerevents/__dir__.ini

@@ -1,2 +1,2 @@
-lsan-allowed: [Alloc, mozilla::dom::ChromeUtils::GenerateQI]
+lsan-allowed: [Alloc, mozilla::dom::ChromeUtils::GenerateQI, EntrySlotOrCreate, mozilla::dom::BrowsingContext_Binding::CreateInterfaceObjects, mozilla::dom::WindowGlobalChild_Binding::CreateInterfaceObjects, mozilla::dom::GetPerInterfaceObjectHandle]
 leak-threshold: [default:153600, tab:307200]