Relax timing a bit

Trying to fix jenkins failure:

com.couchbase.lite.support.BatcherTest > testInvokeProcessorAfterReachingCapacity[hudson_en-US_160_WVGA_android-19_armeabi-v7a_param(AVD) - 4.4.2] [31mFAILED [0m
	junit.framework.AssertionFailedError
	at com.couchbase.lite.support.BatcherTest.testInvokeProcessorAfterReachingCapacity(BatcherTest.java:407)
:connectedAndroidTest FAILED