[wasm] Enable dedup by default. (#80260)

* [wasm] Enable dedup by default.

* [wasm] Enable symbol map for AOT tests too

* MonoAOTCompiler: Fix up the path for the output items if they had been

.. copied to `aot-in` for the compilation step.

Example:
- when using WasmDedup=true, we get the main assemblies in `publish`
directory after linking, but `aot-instances.dll` is in different directory.
- this causes `MonoAOTCompiler` to copy all of them to a temporary `aot-in` dir for compiling with `mono-aot-cross`.
- And when the output items are set, we get:

```
 Output Item(s):
     _WasmAssembliesInternal=
         obj/Debug/net8.0/browser-wasm/wasm/for-publish/aot-in/Debug_u4nbxx3i.gc5.dll
                 LlvmBitcodeFile=obj/Debug/net8.0/browser-wasm/wasm/for-publish/Debug_u4nbxx3i.gc5.dll.bc
```

- here the `ItemSpec` is incorrectly set to the temporary `aot-in` path
- which can cause build failures in the following build steps

* WBT: remove redundant case

Co-authored-by: Ankit Jain <radical@gmail.com>

eng/testing/tests.wasm.targets

@@ -20,7 +20,7 @@
       - for AOT library tests, we use WasmNativeStrip=false, so we already have symbols
     -->
     <WasmNativeStrip Condition="'$(WasmNativeStrip)' == ''">false</WasmNativeStrip>
-    <WasmEmitSymbolMap Condition="'$(WasmEmitSymbolMap)' == '' and '$(RunAOTCompilation)' != 'true'">true</WasmEmitSymbolMap>
+    <WasmEmitSymbolMap Condition="'$(WasmEmitSymbolMap)' == ''">true</WasmEmitSymbolMap>
 
     <!-- Run only if previous command succeeded -->
     <_ShellCommandSeparator Condition="'$(OS)' == 'Windows_NT'">&amp;&amp;</_ShellCommandSeparator>

src/mono/wasm/Wasm.Build.Tests/WasmTemplateTests.cs

@@ -340,7 +340,6 @@ public static TheoryData<string, bool, bool> TestDataForConsolePublishAndRun()
         {
             var data = new TheoryData<string, bool, bool>();
             data.Add("Debug", false, false);
-            data.Add("Debug", false, false);
             data.Add("Debug", false, true);
             data.Add("Release", false, false); // Release relinks by default
 

src/mono/wasm/build/WasmApp.targets

@@ -87,7 +87,7 @@
   -->
 
   <PropertyGroup>
-    <WasmDedup Condition="'$(WasmDedup)' == ''">false</WasmDedup>
+    <WasmDedup Condition="'$(WasmDedup)' == ''">true</WasmDedup>
     <WasmEnableExceptionHandling Condition="'$(WasmEnableExceptionHandling)' == ''">false</WasmEnableExceptionHandling>
     <WasmEnableSIMD Condition="'$(WasmEnableSIMD)' == ''">false</WasmEnableSIMD>
 

src/tasks/AotCompilerTask/MonoAOTCompiler.cs

@@ -560,7 +560,7 @@ private IEnumerable<ITaskItem> EnsureAllAssembliesInTheSameDir(IEnumerable<ITask
 
             ITaskItem newAsm = new TaskItem(newPath);
             asmItem.CopyMetadataTo(newAsm);
-            asmItem.SetMetadata(s_originalFullPathMetadataName, asmPath);
+            newAsm.SetMetadata(s_originalFullPathMetadataName, asmPath);
             newAssemblies.Add(newAsm);
         }
 
@@ -1076,8 +1076,14 @@ private static List<ITaskItem> ConvertAssembliesDictToOrderedList(ConcurrentDict
         List<ITaskItem> outItems = new(originalAssemblies.Count);
         foreach (ITaskItem item in originalAssemblies)
         {
-            if (dict.TryGetValue(item.GetMetadata("FullPath"), out ITaskItem? dictItem))
-                outItems.Add(dictItem);
+            if (!dict.TryGetValue(item.GetMetadata("FullPath"), out ITaskItem? dictItem))
+                continue;
+
+            string originalFullPath = item.GetMetadata(s_originalFullPathMetadataName);
+            if (!string.IsNullOrEmpty(originalFullPath))
+                dictItem.ItemSpec = originalFullPath;
+
+            outItems.Add(dictItem);
         }
         return outItems;
     }