Fix `HomeServer`s leaking during `trial` test runs (#15630)

This change fixes two memory leaks during `trial` test runs.

Garbage collection is disabled during each test case and a gen-0 GC is
run at the end of each test. However, when the gen-0 GC is run, the
`TestCase` object usually still holds references to the `HomeServer`
used during the test. As a result, the `HomeServer` gets promoted to
gen-1 and then never garbage collected.

Fix this by periodically running full GCs.

Additionally, fix `HomeServer`s leaking after tests that touch inbound
federation due to `FederationRateLimiter`s adding themselves to a global
set, by turning the set into a `WeakSet`.

Resolves #15622.

Signed-off-by: Sean Quah <seanq@matrix.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/changelog.d/15630.misc b/changelog.d/15630.misc
new file mode 100644
index 0000000000..a30304bfd6
--- /dev/null
+++ b/changelog.d/15630.misc
@@ -0,0 +1 @@
+Fix two memory leaks in `trial` test runs.