Revert "[osr] Enable concurrent OSR"

This reverts commit 6879c515.

Reason for revert: Speculative revert for roll failures
https://ci.chromium.org/ui/p/chromium/builders/try/win_optional_gpu_tests_rel/80674/overview

Original change's description:
> [osr] Enable concurrent OSR
>
> Fixed: v8:12161
> Change-Id: Ie6e83dd4f261fff2d1fa8613116e83ef6b61561f
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3576116
> Auto-Submit: Jakob Linke <jgruber@chromium.org>
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#79857}

Change-Id: I05bd9594e8ce3db71acb31cf4c626c066158ceaa
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3579163
Owners-Override: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#79890}

src/flags/flag-definitions.h

@@ -880,7 +880,7 @@ DEFINE_BOOL(trace_turbo_inlining, false, "trace TurboFan inlining")
 DEFINE_BOOL(turbo_inline_array_builtins, true,
             "inline array builtins in TurboFan code")
 DEFINE_BOOL(use_osr, true, "use on-stack replacement")
-DEFINE_BOOL(concurrent_osr, true, "enable concurrent OSR")
+DEFINE_BOOL(concurrent_osr, false, "enable concurrent OSR")
 DEFINE_BOOL(trace_osr, false, "trace on-stack replacement")
 DEFINE_BOOL(analyze_environment_liveness, true,
             "analyze liveness of environment slots and zap dead values")

test/cctest/test-js-to-wasm.cc

@@ -271,7 +271,6 @@ class FastJSWasmCallTester {
     i::FLAG_allow_natives_syntax = true;
     i::FLAG_turbo_inline_js_wasm_calls = true;
     i::FLAG_stress_background_compile = false;
-    i::FLAG_concurrent_osr = false;  // Seems to mess with %ObserveNode.
   }
 
   void DeclareCallback(const char* name, FunctionSig* signature,