[release/7.0] Fix test issues on armv6, ppc64le on runtime-community (#75367)

* Fix test issues on armv6, s390x, ppc64le on runtime-community

* Remove s390x Active issue, it will be fixed by another backport

Co-authored-by: Alexander Köplinger <alex.koeplinger@outlook.com>

Author: github-actions[bot]

src/libraries/Common/tests/TestUtilities/System/PlatformDetection.cs

@@ -60,7 +60,9 @@ public static partial class PlatformDetection
         public static bool IsNotArm64Process => !IsArm64Process;
         public static bool IsArmOrArm64Process => IsArmProcess || IsArm64Process;
         public static bool IsNotArmNorArm64Process => !IsArmOrArm64Process;
+        public static bool IsS390xProcess => (int)RuntimeInformation.ProcessArchitecture == 5; // Architecture.S390x
         public static bool IsArmv6Process => (int)RuntimeInformation.ProcessArchitecture == 7; // Architecture.Armv6
+        public static bool IsPpc64leProcess => (int)RuntimeInformation.ProcessArchitecture == 8; // Architecture.Ppc64le
         public static bool IsX64Process => RuntimeInformation.ProcessArchitecture == Architecture.X64;
         public static bool IsX86Process => RuntimeInformation.ProcessArchitecture == Architecture.X86;
         public static bool IsNotX86Process => !IsX86Process;

src/libraries/System.Runtime.InteropServices.RuntimeInformation/tests/CheckArchitectureTests.cs

@@ -29,7 +29,15 @@ public void VerifyArchitecture()
                     break;
 
                 case Architecture.Arm64:
-                    Assert.Equal(IntPtr.Size == 4 ? Architecture.Arm : Architecture.Arm64, processArch);
+                    if (IntPtr.Size == 8)
+                    {
+                        Assert.Equal(Architecture.Arm64, processArch);
+                    }
+                    else
+                    {
+                        // armv7/armv6 process running on arm64 host
+                        Assert.True(processArch == Architecture.Arm || processArch == Architecture.Armv6, $"Unexpected process architecture: {processArch}");
+                    }
                     break;
 
                 case Architecture.Wasm:

src/libraries/System.Runtime.Serialization.Formatters/tests/BinaryFormatterTests.cs

@@ -25,6 +25,7 @@ public partial class BinaryFormatterTests : FileCleanupTestBase
         [ConditionalTheory(typeof(Environment), nameof(Environment.Is64BitProcess))]
         [SkipOnCoreClr("Long running tests: https://github.com/dotnet/runtime/issues/11191", ~RuntimeConfiguration.Release)]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/35915", typeof(PlatformDetection), nameof(PlatformDetection.IsMonoInterpreter))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/75281", typeof(PlatformDetection), nameof(PlatformDetection.IsPpc64leProcess))]
         [InlineData(2 * 6_584_983 - 2)] // previous limit
         [InlineData(2 * 7_199_369 - 2)] // last pre-computed prime number
         public void SerializeHugeObjectGraphs(int limit)