test: fix flaky fix-slots-overflow-for-varg-record

The aforementioned test is flaky when it is run by Tarantool, since the
necessary trace isn't compiled due to hotcount collisions. This patch
fixes this by adding the additional reset of hot counters.

Author: Buristan

test/tarantool-tests/fix-slots-overflow-for-varg-record.test.lua

@@ -89,6 +89,9 @@ wrapper()
 
 assert(not traceinfo(1), 'no traces recorded')
 
+-- Reset hot counters to avoid collisions and blacklisting.
+jit.opt.start('hotloop=1')
+
 -- The simplest trace to compile.
 for _ = 1, 4 do end