don't run LongModuleFileNamesAreSupported test on x86 (for some reason it's flaky)

Author: adamsitnik

src/libraries/System.Diagnostics.Process/tests/ProcessModuleTests.cs

@@ -93,9 +93,10 @@ public void ModulesAreDisposedWhenProcessIsDisposed()
         }
 
         public static bool Is_LongModuleFileNamesAreSupported_TestEnabled
-            => PathFeatures.AreAllLongPathsAvailable() // we want to test long paths
+            => OperatingSystem.IsWindows() // it's specific to Windows
+            && PathFeatures.AreAllLongPathsAvailable() // we want to test long paths
             && !PlatformDetection.IsMonoRuntime // Assembly.LoadFile used the way this test is implemented fails on Mono
-            && OperatingSystem.IsWindowsVersionAtLeast(8); // it's specific to Windows and does not work on Windows 7
+            && PlatformDetection.Is64BitProcess; // for some reason it's flaky on x86
 
         [ConditionalFact(typeof(ProcessModuleTests), nameof(Is_LongModuleFileNamesAreSupported_TestEnabled))]
         public void LongModuleFileNamesAreSupported()