test: Fix test to use a proper interval >0

Previously, the interval was max(6, <interval_value>) which was
changed to actually consider the value of the flag.

Change-Id: Iec3cef19b6ec8528f03c36db6239b044ee90cde1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3487969Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79262}

test/mjsunit/regress/regress-3969.js

@@ -27,7 +27,7 @@ assertEquals("OK", outer.boom());
 assertEquals("OK", outer.boom());
 
 inner = undefined;
-%SetAllocationTimeout(0 /*interval*/, 2 /*timeout*/);
+%SetAllocationTimeout(6 /*interval*/, 2 /*timeout*/);
 // Call something that will do GC while holding a handle to outer's map.
 // The key is that this lets inner's map die while keeping outer's map alive.
 delete outer.inner;