Use bit patterns for comparing zeroes instead of signbit

Co-authored-by: Davis Bennett <davis.v.bennett@gmail.com>

Author: bojidar-bg

src/zarr/core/buffer/core.py

@@ -524,11 +524,8 @@ def all_equal(self, other: Any, equal_nan: bool = True) -> bool:
             # Handle None fill_value for Zarr V2
             return False
         if other == 0.0 and self._data.dtype.kind not in ("U", "S", "T", "O", "V"):
-            # Handle positive and negative zero
-            if np.any(self._data):  # Check for any truthy value
-                return False
-            # Check signs:
-            return np.array_equiv(np.signbit(self._data), np.signbit(other))
+            # Handle positive and negative zero by comparing bit patterns:
+            return np.array_equiv(np.array(self._data).view("V"), np.array(other).view("V"))
         # use array_equal to obtain equal_nan=True functionality
         # Since fill-value is a scalar, isn't there a faster path than allocating a new array for fill value
         # every single time we have to write data?