[wasm] Enable wasm relinking by default for Release config (#49251)

* [wasm] Set default value for $(WasmBuildNative) based on:

- If $(WasmBuildNative) is already set (eg. by user project) to true, then error if EMSDK_PATH is unset
- if unset, and$(PublishTrimmed) == false, then set to false
- if unset, and $(Configuration) == "Release", then set to true
- If it is $(WasmBuildNative) == true after above steps, and emsdk is missing
    => then emit a warning, and set it to false

commits:

* [wasm] Set WasmBuildNative=true for Release config

- But set to `false` if `$(PublishTrimmed)` is not true

Fixes: https://github.com/dotnet/runtime/issues/48349

* dotnet-linker-tests need mono-aot-cross

* [wasm] Cleanup setting emcc flags

* Address review feedback from @lewing

.. and update tests to track the changes.

* Correctly address review feedback:

1 files changed, 4 insertions, 3 deletions

diff --git a/src/tests/BuildWasmApps/Wasm.Build.Tests/WasmBuildAppTest.cs b/src/tests/BuildWasmApps/Wasm.Build.Tests/WasmBuildAppTest.cs
index c6ff9aa45d3..29b31eea76d 100644
--- a/src/tests/BuildWasmApps/Wasm.Build.Tests/WasmBuildAppTest.cs
+++ b/src/tests/BuildWasmApps/Wasm.Build.Tests/WasmBuildAppTest.cs
@@ -176,7 +176,8 @@ namespace Wasm.Build.Tests
 
             string projectName = $"invariant_{invariantGlobalization?.ToString() ?? "unset"}";
             BuildProject(projectName, config, aot: aot, extraProperties: extraProperties,
-                        hasIcudt: invariantGlobalization == null || invariantGlobalization.Value == false);
+                        hasIcudt: invariantGlobalization == null || invariantGlobalization.Value == false,
+                        dotnetWasmFromRuntimePack: !(aot || config == "Release"));
 
             RunAndTestWasmApp(projectName, config, isAOT: aot, expectedExitCode: 42,
                                 test: output => Assert.Contains("Hello, World!", output));
@@ -265,7 +266,7 @@ namespace Wasm.Build.Tests
         void TestMain(string projectName, string programText, string config, bool aot)
         {
             File.WriteAllText(Path.Combine(_tempDir, "Program.cs"), programText);
-            BuildProject(projectName, config, aot: aot);
+            BuildProject(projectName, config, aot: aot, dotnetWasmFromRuntimePack: !(aot || config == "Release"));
             RunAndTestWasmApp(projectName, config, isAOT: aot, expectedExitCode: 42,
                                 test: output => Assert.Contains("Hello, World!", output));
         }
@@ -281,7 +282,7 @@ namespace Wasm.Build.Tests
             string programText = programFormatString.Replace("##CODE##", code);
 
             File.WriteAllText(Path.Combine(_tempDir, "Program.cs"), programText);
-            BuildProject(projectName, config, aot: aot);
+            BuildProject(projectName, config, aot: aot, dotnetWasmFromRuntimePack: !(aot || config == "Release"));
             RunAndTestWasmApp(projectName, config, isAOT: aot, expectedExitCode: 42 + args.Length, args: string.Join(' ', args),
                 test: output =>
                 {