[test] Add gc-interval flag to deopt-pretenure test

mjsunit/compiler/deopt-pretenure.js is flaky due to --gc-interval in
some variants.
The flag can cause a variable to be promoted to old space before the
test can force allocation site pretenuring for that variable, which is
essential for the test case.

Bug: v8:12652
Change-Id: If7239deaa3026bb781d3ee96df28a1bbf3a5b6f1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3488371
Auto-Submit: Patrick Thier <pthier@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79275}

test/mjsunit/compiler/deopt-pretenure.js

@@ -4,7 +4,7 @@
 
 // Flags: --allow-natives-syntax --opt --no-always-opt
 // Flags: --allocation-site-pretenuring --stress-gc-during-compilation
-// Flags: --stress-scavenge=0
+// Flags: --stress-scavenge=0 --gc-interval=-1
 // Flags: --max-optimized-bytecode-size=132000
 
 function CheckOptimizationStatus(func, expectedOptimizationStatus) {