[wasm] Enabled WriteToReadOnly tests - emscripten bug got fixed (#70814)

Fixes #53021.

Enabled tests from #53021 - they are passing now because issue reported by @radekdoulik got fixed: https://github.com/emscripten-core/emscripten/issues/14299.

src/libraries/System.IO.FileSystem/tests/File/ReadWriteAllBytes.cs

@@ -86,7 +86,6 @@ public void OpenFile_ThrowsIOException()
         /// file is allowed.
         /// </summary>
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/53021", TestPlatforms.Browser)]
         public void WriteToReadOnlyFile()
         {
             string path = GetTestFilePath();

src/libraries/System.IO.FileSystem/tests/File/ReadWriteAllBytesAsync.cs

@@ -97,7 +97,6 @@ public async Task OpenFile_ThrowsIOExceptionAsync()
         /// file is allowed.
         /// </summary>
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/53021", TestPlatforms.Browser)]
         public async Task WriteToReadOnlyFileAsync()
         {
             string path = GetTestFilePath();

src/libraries/System.IO.FileSystem/tests/File/ReadWriteAllLines.cs

@@ -118,7 +118,6 @@ public void Read_FileNotFound()
         /// file is allowed.
         /// </summary>
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/53021", TestPlatforms.Browser)]
         public void WriteToReadOnlyFile()
         {
             string path = GetTestFilePath();
@@ -307,7 +306,6 @@ public void Read_FileNotFound()
         /// file is allowed.
         /// </summary>
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/53021", TestPlatforms.Browser)]
         public void WriteToReadOnlyFile()
         {
             string path = GetTestFilePath();

src/libraries/System.IO.FileSystem/tests/File/ReadWriteAllLinesAsync.cs

@@ -113,7 +113,6 @@ public async Task OpenFile_ThrowsIOExceptionAsync()
         /// file is allowed.
         /// </summary>
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/53021", TestPlatforms.Browser)]
         public async Task WriteToReadOnlyFile()
         {
             string path = GetTestFilePath();

src/libraries/System.IO.FileSystem/tests/File/ReadWriteAllText.cs

@@ -131,7 +131,6 @@ public void Read_FileNotFound()
         /// file is allowed.
         /// </summary>
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/53021", TestPlatforms.Browser)]
         public void WriteToReadOnlyFile()
         {
             string path = GetTestFilePath();

src/libraries/System.IO.FileSystem/tests/File/ReadWriteAllTextAsync.cs

@@ -122,7 +122,6 @@ public async Task OpenFile_ThrowsIOExceptionAsync()
         /// file is allowed.
         /// </summary>
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/53021", TestPlatforms.Browser)]
         public async Task WriteToReadOnlyFileAsync()
         {
             string path = GetTestFilePath();

src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedFile.CreateFromFile.Tests.cs

@@ -699,7 +699,6 @@ private void WriteToReadOnlyFile(MemoryMappedFileAccess access, bool succeeds)
         [Theory]
         [InlineData(MemoryMappedFileAccess.Read)]
         [InlineData(MemoryMappedFileAccess.ReadWrite)]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/53021", TestPlatforms.Browser)]
         public void WriteToReadOnlyFile_ReadWrite(MemoryMappedFileAccess access)
         {
             WriteToReadOnlyFile(access, access == MemoryMappedFileAccess.Read ||
@@ -707,7 +706,6 @@ public void WriteToReadOnlyFile_ReadWrite(MemoryMappedFileAccess access)
         }
 
         [Fact]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/53021", TestPlatforms.Browser)]
         public void WriteToReadOnlyFile_CopyOnWrite()
         {
             WriteToReadOnlyFile(MemoryMappedFileAccess.CopyOnWrite, PlatformDetection.IsSuperUser);