GeckoEngineSession#onHistoryStateChange: it.title must not be null

[grigoryk]

From https://sentry.prod.mozaws.net/operations/firefox/issues/9265306/?query=is%3Aunresolved%20release%3Aorg.mozilla.firefox-79.0.4

Pretty decent volume of crashes.

java.lang.IllegalStateException: it.title must not be null
    at kotlin.jvm.internal.ArrayIteratorKt.checkExpressionValueIsNotNull(ArrayIterator.kt:1)
    at mozilla.components.browser.engine.gecko.GeckoEngineSession$createHistoryDelegate$1.onHistoryStateChange(GeckoEngineSession.kt:4)
    at org.mozilla.geckoview.GeckoSession$1.handleMessage(GeckoSession.java:24)
    at org.mozilla.geckoview.GeckoSession$1.handleMessage(GeckoSession.java:1)
    at org.mozilla.geckoview.GeckoSessionHandler.handleMessage(GeckoSessionHandler.java:2)
    at org.mozilla.gecko.EventDispatcher$3.run(EventDispatcher.java:1)
    at android.os.Handler.handleCallback(Handler.java:873)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:216)
    at android.app.ActivityThread.main(ActivityThread.java:7266)
    at java.lang.reflect.Method.invoke(Method.java)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:975)

┆Issue is synchronized with this Jira Task

[grigoryk]

Introduced in #7024, where we falsely assume that GV won't pass us null titles.

[grigoryk]

cc @jonalmeida @NotWoods

[agi]

gv bug https://bugzilla.mozilla.org/show_bug.cgi?id=1660286