Docs: Minor edit to IR docs to mention longer intial/clean builds
Docs: Minor edit to IR docs to mention longer intial/clean builds

Change-Id: Ie2727cc98bbcf756ae160cbdd160847cec550e0f

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base