[dotnet/monotouch-test] Disable tests that require Crypto for .NET.

[rolfbjarne]

Crypto hasn't been implemented yet in .NET for iOS.

This fixes a crash because these tests cause an unhandled exception on the
finalizer thread (which crashes the process):

Unhandled Exception:
System.EntryPointNotFoundException: AppleCryptoNative_SecKeychainItemCopyKeychain assembly:<unknown assembly> type:<unknown type> member:(null)
   at Interop.AppleCrypto.SecKeychainItemCopyKeychain(IntPtr item)
   at System.Security.Cryptography.Apple.SafeTemporaryKeychainHandle.UntrackItem(IntPtr keychainItem)
   at System.Security.Cryptography.Apple.SafeKeychainItemHandle.ReleaseHandle()
   at System.Runtime.InteropServices.SafeHandle.InternalRelease(Boolean disposeOrFinalizeOperation)
   at System.Runtime.InteropServices.SafeHandle.Dispose(Boolean disposing)
   at System.Runtime.InteropServices.SafeHandle.Finalize()

=================================================================
	Native Crash Reporting
=================================================================
Got a abrt while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries
used by your application.
=================================================================

=================================================================
	Native stacktrace:
=================================================================
	0x108bfc396 - /Users/rolf/Library/Developer/CoreSimulator/Devices/289E372A-501C-4499-A1A6-59C5B3B6A9AE/data/Containers/Bundle/Application/A23AD847-E868-4895-ADBA-036D4E87BA35/monotouchtest.app/libmonosgen-2.0.dylib : mono_dump_native_crash_info
	0x108ba878f - /Users/rolf/Library/Developer/CoreSimulator/Devices/289E372A-501C-4499-A1A6-59C5B3B6A9AE/data/Containers/Bundle/Application/A23AD847-E868-4895-ADBA-036D4E87BA35/monotouchtest.app/libmonosgen-2.0.dylib : mono_handle_native_crash
	0x108bfbbed - /Users/rolf/Library/Developer/CoreSimulator/Devices/289E372A-501C-4499-A1A6-59C5B3B6A9AE/data/Containers/Bundle/Application/A23AD847-E868-4895-ADBA-036D4E87BA35/monotouchtest.app/libmonosgen-2.0.dylib : sigabrt_signal_handler
	0x7fff51c005fd - /Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 13.5.simruntime/Contents/Resources/RuntimeRoot/usr/lib/system/libsystem_platform.dylib : _sigtramp
	0x0 - Unknown
	0x7fff51af0b7c - /Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 13.5.simruntime/Contents/Resources/RuntimeRoot/usr/lib/system/libsystem_c.dylib : abort
	0x1089bf7ef - /Users/rolf/Library/Developer/CoreSimulator/Devices/289E372A-501C-4499-A1A6-59C5B3B6A9AE/data/Containers/Bundle/Application/A23AD847-E868-4895-ADBA-036D4E87BA35/monotouchtest.app/libxamarin-debug.dylib : xamarin_unhandled_exception_handler
	0x108c69548 - /Users/rolf/Library/Developer/CoreSimulator/Devices/289E372A-501C-4499-A1A6-59C5B3B6A9AE/data/Containers/Bundle/Application/A23AD847-E868-4895-ADBA-036D4E87BA35/monotouchtest.app/libmonosgen-2.0.dylib : mono_invoke_unhandled_exception_hook
	0x108cc688c - /Users/rolf/Library/Developer/CoreSimulator/Devices/289E372A-501C-4499-A1A6-59C5B3B6A9AE/data/Containers/Bundle/Application/A23AD847-E868-4895-ADBA-036D4E87BA35/monotouchtest.app/libmonosgen-2.0.dylib : mono_thread_internal_unhandled_exception
	0x108cf5ad5 - /Users/rolf/Library/Developer/CoreSimulator/Devices/289E372A-501C-4499-A1A6-59C5B3B6A9AE/data/Containers/Bundle/Application/A23AD847-E868-4895-ADBA-036D4E87BA35/monotouchtest.app/libmonosgen-2.0.dylib : mono_gc_run_finalize
	0x108d0f095 - /Users/rolf/Library/Developer/CoreSimulator/Devices/289E372A-501C-4499-A1A6-59C5B3B6A9AE/data/Containers/Bundle/Application/A23AD847-E868-4895-ADBA-036D4E87BA35/monotouchtest.app/libmonosgen-2.0.dylib : sgen_gc_invoke_finalizers
	0x108cf73cf - /Users/rolf/Library/Developer/CoreSimulator/Devices/289E372A-501C-4499-A1A6-59C5B3B6A9AE/data/Containers/Bundle/Application/A23AD847-E868-4895-ADBA-036D4E87BA35/monotouchtest.app/libmonosgen-2.0.dylib : finalizer_thread
	0x108cc7081 - /Users/rolf/Library/Developer/CoreSimulator/Devices/289E372A-501C-4499-A1A6-59C5B3B6A9AE/data/Containers/Bundle/Application/A23AD847-E868-4895-ADBA-036D4E87BA35/monotouchtest.app/libmonosgen-2.0.dylib : start_wrapper_internal
	0x108cc6f39 - /Users/rolf/Library/Developer/CoreSimulator/Devices/289E372A-501C-4499-A1A6-59C5B3B6A9AE/data/Containers/Bundle/Application/A23AD847-E868-4895-ADBA-036D4E87BA35/monotouchtest.app/libmonosgen-2.0.dylib : start_wrapper
	0x7fff51c0c109 - /Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 13.5.simruntime/Contents/Resources/RuntimeRoot/usr/lib/system/libsystem_pthread.dylib : _pthread_start
	0x7fff51c07b8b - /Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 13.5.simruntime/Contents/Resources/RuntimeRoot/usr/lib/system/libsystem_pthread.dylib : thread_start

[monojenkins]

Build success
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