…8209)

Repeatedly calling `getIsolate` results in variables currently in scope
in the top frame of the isolate at the time of the request being
assigned object IDs, inserting them into the VM service's object ID ring
buffer. This keeps the objects alive until the buffer wraps around,
which can cause OOM exceptions if the target application is repeatedly
making large, temporary allocations that would otherwise be GC'd.

The logic has been updated to rely on SentinelExceptions and the Isolate
event stream to determine when an isolate is no longer relevant and
should be removed from the memory chart statistics.

Fixes #8180

…e local tags (#8257)

…er version file (#8259)