System property that instructs Spring to ignore the index, i.e.
to always return null from loadIndex(ClassLoader).
The default is "false", allowing for regular use of the index. Switching this
flag to true fulfills a corner case scenario when an index is partially
available for some libraries (or use cases) but couldn't be built for the whole
application. In this case, the application context fallbacks to a regular
classpath arrangement (i.e. as no index was present at all).