[Benchmark] Fix warnings around usage of __COUNTER__ (llvm#184524)

Premerge CI is currently failing with the following after the update to
clang v22:

```
/home/gha/llvm-project/clang-tools-extra/clangd/benchmarks/IndexBenchmark.cpp:92:1: error: '__COUNTER__' is a C2y extension [-Werror,-Wc2y-extensions]
   92 | BENCHMARK(dexQueries);
      | ^
```

Some original work was done around this in
df1d786, which was then done in
upstream Google benchmark in

google/benchmark@d8db2f9.
The original work done in the patch implementing this feature doesn't
seem to account for as many cases as the upstream patch does. This patch
reverts the diff in df1d786 and applies
the applicable hunks from the upstream patch.

Author: boomanaiden154

third-party/benchmark/include/benchmark/benchmark.h

@@ -1459,14 +1459,29 @@ class Fixture : public internal::Benchmark {
 // ------------------------------------------------------
 // Macro to register benchmarks
 
+// clang-format off
+#if defined(__clang__)
+#define BENCHMARK_DISABLE_COUNTER_WARNING                        \
+  _Pragma("GCC diagnostic push")                                 \
+  _Pragma("GCC diagnostic ignored \"-Wunknown-warning-option\"") \
+  _Pragma("GCC diagnostic ignored \"-Wc2y-extensions\"")
+#define BENCHMARK_RESTORE_COUNTER_WARNING _Pragma("GCC diagnostic pop")
+#else
+#define BENCHMARK_DISABLE_COUNTER_WARNING
+#define BENCHMARK_RESTORE_COUNTER_WARNING
+#endif
+// clang-format on
+
 // Check that __COUNTER__ is defined and that __COUNTER__ increases by 1
 // every time it is expanded. X + 1 == X + 0 is used in case X is defined to be
 // empty. If X is empty the expression becomes (+1 == +0).
+BENCHMARK_DISABLE_COUNTER_WARNING
 #if defined(__COUNTER__) && (__COUNTER__ + 1 == __COUNTER__ + 0)
 #define BENCHMARK_PRIVATE_UNIQUE_ID __COUNTER__
 #else
 #define BENCHMARK_PRIVATE_UNIQUE_ID __LINE__
 #endif
+BENCHMARK_RESTORE_COUNTER_WARNING
 
 // Helpers for generating unique variable names
 #ifdef BENCHMARK_HAS_CXX11
@@ -1485,8 +1500,9 @@ class Fixture : public internal::Benchmark {
   BaseClass##_##Method##_Benchmark
 
 #define BENCHMARK_PRIVATE_DECLARE(n)                                 \
+  BENCHMARK_DISABLE_COUNTER_WARNING                                  \
   static ::benchmark::internal::Benchmark* BENCHMARK_PRIVATE_NAME(n) \
-      BENCHMARK_UNUSED
+      BENCHMARK_RESTORE_COUNTER_WARNING BENCHMARK_UNUSED
 
 #ifdef BENCHMARK_HAS_CXX11
 #define BENCHMARK(...)                                               \