Skip flaky test

tests/ImageSharp.Tests/Memory/Allocators/ArrayPoolMemoryAllocatorTests.cs

@@ -95,18 +95,9 @@ public unsafe void SmallBuffersArePooled_OfBigValueType()
             Assert.True(this.LocalFixture.CheckIsRentingPooledBuffer<LargeStruct>(count));
         }
 
-        [Fact]
+        [Fact(Skip = "It looks like the GC is forming an unmanaged pool which makes this test flaky.")]
         public unsafe void LargeBuffersAreNotPooled_OfBigValueType()
         {
-            if (!TestEnvironment.IsWindows)
-            {
-                // TODO: We should have an attribute for this kind of stuff.
-                // This test passes locally but not in the UNIX CI.
-                // This could be due to the GC simply returning the same buffer
-                // from unmanaged memory but this requires confirmation.
-                return;
-            }
-
             int count = (MaxPooledBufferSizeInBytes / sizeof(LargeStruct)) + 1;
 
             Assert.False(this.LocalFixture.CheckIsRentingPooledBuffer<LargeStruct>(count));