[clang-tidy] Use bool literals

See
https://clang.llvm.org/extra/clang-tidy/checks/modernize-use-bool-literals.html.

Bug: v8:10488
Change-Id: I0808eee42c3339d9de653125b0d853b8ae5e5540
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2233856Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68243}

src/libsampler/sampler.h

@@ -72,7 +72,7 @@ class V8_EXPORT_PRIVATE Sampler {
 
  protected:
   // Counts stack samples taken in various VM states.
-  bool is_counting_samples_ = 0;
+  bool is_counting_samples_ = false;
   unsigned js_sample_count_ = 0;
   unsigned external_sample_count_ = 0;