OutOfMemoryError triggered by atlassian-profiling

Heap dump #2 of SSP-7301 shows an atlassian-profiler ProfilingTimerBean for request "GET /rest/remote-link-aggregation/latest/aggregation" taking up 275MB of retained size.

Drilling down into the trace shows 889672 nested calls to PermissionService.isRepositoryAccessible each of which is 304 bytes. This alone is responsible for 257 Mb, so there's probably a bit more going on.

We need to

• Exclude our high frequently called methods (e.g. anything on PermissionService) from profiling
• Investigate why remote-link-aggregating involves so many permission checks
• Check whether we can make atlassian-profiler smart enough to stop profiling once it has accumulated more than 500 or 1000 elements in the tree.