Fix flakes in store-data-property-in-literal-private.js

In stress runs a GC may kick in before assertOptimized() is called
on the optimized function, causing it to deoptimize and the test
would fail even if the function is optimized as expected.
Adding --no-stress-flush-code --no-flush-bytecode fixes the timing
issue.

Bug: v8:12332
Change-Id: If43c2a06e84c0e3b5e21f7bde160340a0fc742f4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3237326Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Joyee Cheung <joyee@igalia.com>
Cr-Commit-Position: refs/heads/main@{#77645}

test/mjsunit/compiler/store-data-property-in-literal-private.js

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --allow-natives-syntax --opt --trace-opt --trace-deopt
+// Flags: --no-stress-flush-code --no-flush-bytecode
 let privateSymbol = %CreatePrivateSymbol("private");
 let privateName = %CreatePrivateNameSymbol("privateName");