[dotnet] Disable dedup optimization if we're interpreting every assem…

…bly. (#21661)

This speeds up the inner dev loop, because:

* The dedup assembly must be AOT-compiled for arm64
* arm64 is the default target architecture on more and more devices/macs
* AOT-compilation is slow

So disabling the dedup optimization in this case makes the build faster,
because we don't have to AOT-compile something that doesn't exist.

Build times of a new MAUI app (`dotnet new maui`):

| -                              | with dedup   | without dedup |
| ------------------------------ | -----------: | ------------: |
| Simulator (Debug)              |         18 s |           8 s |
| Device (Debug)                 |         32 s |          22 s |
| Device (Release, interpreter)  |         43 s |          18 s |
| Device (Release, fullaot)      |       1m20 s |        1m40 s |

App size:

| -                              | with dedup | without dedup |
| ------------------------------ | ---------: | ------------: |
| Device (Debug)                 |     126 MB |         88 MB |
| Device (Release, interpreter)  |      19 MB |         14 MB |
| Device (Release, fullaot)      |      42 MB |         69 MB |

Note that disabling dedup when using the interpreter makes the app
smaller as well.

dotnet/targets/Xamarin.Shared.Sdk.targets

@@ -1116,7 +1116,7 @@
 				In such setup, during runtime, AOT images are loaded but marked as unusuable as they are compiled with `full` compiler switch and the code falls back to interpreter.
 				Dedup AOT image is specially handled by the AOT runtime and it is not allowed to have it marked as unusuable.
 			-->
-			<_IsDedupEnabled Condition="'$(_IsDedupEnabled)' == '' And '$(_RunAotCompiler)' == 'true' And '$(IsMacEnabled)' == 'true' And '$(TargetArchitectures)' == 'ARM64'">true</_IsDedupEnabled>
+			<_IsDedupEnabled Condition="'$(_IsDedupEnabled)' == '' And '$(_RunAotCompiler)' == 'true' And '$(IsMacEnabled)' == 'true' And '$(TargetArchitectures)' == 'ARM64' And '$(MtouchInterpreter)' != 'all'">true</_IsDedupEnabled>
 			<_DedupAssembly Condition="'$(_IsDedupEnabled)' == 'true'">$(IntermediateOutputPath)aot-instances.dll</_DedupAssembly>
 
 			<!-- default to 'static' for Mac Catalyst to work around https://github.com/xamarin/xamarin-macios/issues/14686 -->