s2loop_measures_test GetSignedArea.ErrorAccumulation fails on macOS

Unclear if this is a problem with the allowed error threshold or the code.

```
[ RUN ] GetSignedArea.ErrorAccumulation
.../s2geometry/src/s2/s2loop_measures_test.cc:286: Failure
The difference between expected_area and actual_area is 3.5813685350660762e-11, which exceeds allowed_error, where
expected_area evaluates to 0.78539816339744795,
actual_area evaluates to 0.78539816336163426, and
allowed_error evaluates to 3.4879033766936103e-11.

[ FAILED ] GetSignedArea.ErrorAccumulation (343 ms)
```

```
% c++ --version
Apple clang version 15.0.0 (clang-1500.1.0.2.5)
Target: arm64-apple-darwin22.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
```