Merge "Switch some deprecated variables to obsolete"

# Mark variables deprecated/obsolete

CHANGES_URL := https://android.googlesource.com/platform/build/+/master/Changes.md

$(KATI_deprecated_var PATH,Do not use PATH directly. See $(CHANGES_URL)#PATH)

$(KATI_obsolete_var PATH,Do not use PATH directly. See $(CHANGES_URL)#PATH)

$(KATI_obsolete_var PYTHONPATH,Do not use PYTHONPATH directly. See $(CHANGES_URL)#PYTHONPATH)

$(KATI_obsolete_var OUT,Use OUT_DIR instead. See $(CHANGES_URL)#OUT)

$(KATI_obsolete_var ANDROID_HOST_OUT,Use HOST_OUT instead. See $(CHANGES_URL)#ANDROID_HOST_OUT)

$(KATI_deprecated_var ANDROID_PRODUCT_OUT,Use PRODUCT_OUT instead. See $(CHANGES_URL)#ANDROID_PRODUCT_OUT)

$(KATI_obsolete_var ANDROID_PRODUCT_OUT,Use PRODUCT_OUT instead. See $(CHANGES_URL)#ANDROID_PRODUCT_OUT)

$(KATI_obsolete_var ANDROID_HOST_OUT_TESTCASES,Use HOST_OUT_TESTCASES instead. See $(CHANGES_URL)#ANDROID_HOST_OUT_TESTCASES)

$(KATI_obsolete_var ANDROID_TARGET_OUT_TESTCASES,Use TARGET_OUT_TESTCASES instead. See $(CHANGES_URL)#ANDROID_TARGET_OUT_TESTCASES)

$(KATI_deprecated_var ANDROID_BUILD_TOP,Use '.' instead. See $(CHANGES_URL)#ANDROID_BUILD_TOP)