test: fix flaky OOM error frame test

This test could do allocation outside of the protected frame,
which could result in an uncaught OOM and test failure. This
patch adds extra `collectgarbage` calls to the test to avoid
such situations.

Reviewed-by: Sergey Kaplun <[email protected]>
Reviewed-by: Sergey Bronnikov <[email protected]>
Signed-off-by: Igor Munkin <[email protected]>

Author: mkokryashkin

test/tarantool-tests/lj-1004-oom-error-frame.test.lua

@@ -10,6 +10,8 @@ test:plan(2)
 
 local testoomframe = require('testoomframe')
 
+collectgarbage()
+
 local anchor_memory = {} -- luacheck: no unused
 local function eatchunks(size)
   while true do
@@ -34,6 +36,11 @@ local function chomp()
 end
 
 local st, err = pcall(chomp)
+
+-- Prevent OOM outside of the protected frame.
+anchor_memory = nil
+collectgarbage()
+
 test:ok(st == false, 'on-trace error handled successfully')
 test:like(err, 'not enough memory', 'error is OOM')
 test:done(true)