zpaq: use assertion instead of test return value

Closes #29483.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Upgrades the Java, Python and 32/64 bit Go Google App Engine SDKs to 1.9.5. SHAs taken from Google's download site at https://developers.google.com/appengine/downloads
app-engine-java-sdk: add 1.9.5 bottle.
go-app-engine-64: add 1.9.5 bottle.
go-app-engine-32: add 1.9.5 bottle.
google-app-engine: add 1.9.5 bottle.