Run tests with .NET 9.0

[julienp]

Add .NET 9.0 to the CI test matrix

[julienp]

Getting an error due to extra output that causes the port parsing to fail:

error: testprovider (resource) plugin [D:\a\pulumi-dotnet\pulumi-dotnet\integration_tests\testprovider\pulumi-resource-testprovider.exe] wrote a non-numeric port to stdout ('0'): strconv.Atoi: parsing "\x1b]9;4;3;\x1b\\\x1b]9;4;0;\x1b\\49365": invalid syntax

The port is written here

pulumi-dotnet/sdk/Pulumi/Provider/Provider.cs

Line 438 in 20ef369

stdout.Write(port.ToString() + "\n");

Interestingly, when I changed that line to be stdout.Write("banana" + port.ToString() + "\n");, I got the expected output and no ansi escape codes.

This only happens on .NET 9, and only in CI.

[julienp]

@Frassle found the issue dotnet/msbuild#10998

[julienp]

Workaround in CLI pulumi/pulumi#17783

Once that's released, we can do the upgrade here.