Use timespec_get on iOS/tvOS/MacCatalyst now that 13.0 is the minimum version (#130246)

`timespec_get` was previously unavailable on iOS/tvOS/MacCatalyst below
13.0, so `LogAssert` in `debug.cpp` fell back to `gettimeofday` for
those platforms. Since 13.0 is now the minimum deployment target, that
fallback is no longer needed there.

## Changes

- **`src/coreclr/utilcode/debug.cpp`**: Remove `HOST_IOS`, `HOST_TVOS`,
and `HOST_MACCATALYST` from the `gettimeofday` fallback condition —
`timespec_get` is now used directly on those platforms. `HOST_ANDROID`
retains the fallback since targeted Android API levels still lack
`timespec_get` support.

```c
// Before
#if defined(HOST_IOS) || defined(HOST_TVOS) || defined(HOST_MACCATALYST) || defined(HOST_ANDROID)
    // timespec_get is only available on iOS 13.0+ and not supported on Android API levels we target

// After
#if defined(HOST_ANDROID)
    // timespec_get is not supported on Android API levels we target
```

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: BrzVlad <4720621+BrzVlad@users.noreply.github.com>

Author: Copilot

src/coreclr/utilcode/debug.cpp

@@ -163,8 +163,8 @@ VOID LogAssert(
     STRESS_LOG2(LF_ASSERT, LL_ALWAYS, "ASSERT:%s:%d\n", szFile, iLine);
 
     struct timespec ts;
-#if defined(HOST_IOS) || defined(HOST_TVOS) || defined(HOST_MACCATALYST) || defined(HOST_ANDROID)
-    // timespec_get is only available on iOS 13.0+ and not supported on Android API levels we target, use gettimeofday instead
+#if defined(HOST_ANDROID)
+    // timespec_get is not supported on Android API levels we target, use gettimeofday instead
     struct timeval tv;
     gettimeofday(&tv, nullptr);
     ts.tv_sec = tv.tv_sec;