lisa.tests.base: Use LRU cache for TestBundle.trace
lisa.tests.base: Use LRU cache for TestBundle.trace

Avoid storing the parsed trace forever, to avoid consuming too much
memory in processes manipulating a large number of TestBundle. Most of
these kind of scripts will only process a bundle once and then go to the
next one anyway.

credp/lisa,ARM-software/lisa,ARM-software/lisa,credp/lisa,credp/lisa,credp/lisa,ARM-software/lisa,ARM-software/lisa