Merge bitcoin/bitcoin#28697: fuzz: Increase merge -rss_limit_mb

fa21535 fuzz: Increase merge -rss_limit_mb (MarcoFalke)

Pull request description:

  For some reason, the limit is hit. (Presumably due to `-set_cover_merge=1` eating more memory, or by simply having more fuzz inputs).

  Fix it by increasing it for the merge operation.

ACKs for top commit:
  dergoegge:
    ACK fa21535
  hebasto:
    ACK fa21535, considering the discussion in bitcoin-core/qa-assets#155.

Tree-SHA512: 4fed0f254eccc6fe0b53656bc345ff898b13811dc39387387317d34b521ab77cee03d82b0896dd92d253b7546b6a7e4bdcd478749f47064374ab44ad759ab9ff

Author: fanquake

test/fuzz/test_runner.py

@@ -277,6 +277,7 @@ def merge_inputs(*, fuzz_pool, corpus, test_list, src_dir, build_dir, merge_dirs
     for t in test_list:
         args = [
             os.path.join(build_dir, 'src', 'test', 'fuzz', 'fuzz'),
+            '-rss_limit_mb=8000',
             '-set_cover_merge=1',
             # set_cover_merge is used instead of -merge=1 to reduce the overall
             # size of the qa-assets git repository a bit, but more importantly,