[wasm] Fix running debugger tests on windows (#87228)

* [wasm] Fix running debugger tests on windows

.. by making sure to escape `&` in the command line. This was introduced
in:

```
commit e96321d
Author: Ilona Tomkowicz <[email protected]>
Date:   Tue Jun 6 05:59:43 2023 +0200

    [wasm][debugger] Disable failing multithreading debugger tests (#86501)
```

.. but missed CI due to the helix outage.

* Fix escaping ! on windows

Author: radical

src/mono/wasm/debugger/Wasm.Debugger.Tests/wasm.helix.targets

@@ -27,7 +27,7 @@
         <PayloadArchive>$(TestArchiveTestsDir)Wasm.Debugger.Tests.zip</PayloadArchive>
         <Command>$(HelixCommand)</Command>
         <Timeout>$(_DebuggerTestsWorkItemTimeout)</Timeout>
-        <PreCommands Condition="'$(OS)' == 'Windows_NT'">set &quot;TEST_ARGS=--filter category!=failing&amp;FullyQualifiedName~%(Identity)&quot;</PreCommands>
+        <PreCommands Condition="'$(OS)' == 'Windows_NT'">set &quot;TEST_ARGS=--filter category^^!=failing^&amp;FullyQualifiedName~%(Identity)&quot;</PreCommands>
         <PreCommands Condition="'$(OS)' != 'Windows_NT'">export &quot;TEST_ARGS=--filter category!=failing&amp;FullyQualifiedName~%(Identity)&quot;</PreCommands>
       </HelixWorkItem>
     </ItemGroup>