VZ regression: kernel decompression is broken in master

[AkihiroSuda]

This PR disables kernel decompression for vz instances.
before:

lima/pkg/vz/disk.go

Line 45 in b94e2fc

if _, err := fileutils.DownloadFile(ctx, kernel, f.Kernel.File, true, "the kernel", *driver.Instance.Config.Arch); err != nil {

after:

lima/pkg/instance/start.go

Line 120 in d32847c

if _, err := fileutils.DownloadFile(ctx, kernel, f.Kernel.File, false, "the kernel", *inst.Config.Arch); err != nil {

Since vz doesn’t support compressed kernels, booting with one causes the VM to fail with an internal error:

{"level":"fatal","msg":"Error Domain=VZErrorDomain Code=1 Description="Internal Virtualization error. The virtual machine failed to start." UserInfo={\n NSLocalizedFailure = "Internal Virtualization error.";\n NSLocalizedFailureReason = "The virtual machine failed to start.";\n}","time":"2025-07-09T09:48:08+09:00"}

Originally posted by @norio-nomura in #3691 (comment)