b/ci: update build container to Fedora 35

Fedora 32 is EOL since over half a year, update to the current stable
Fedora release.

toolchains: adds clang as it's no longer part of the llvm package,
changes toolchain path references to GCC 11, and rebuilds the sysroot.

edk2: update to latest stable (old version cannot build with a newer
minor version of Python 3) and patch to disable -Werror and make the
newer included Brotli version work as it natively includes BUILD
files which need to be patched out to make the source files accessible.

linux: add patch to fix PVH ELF note entrypoint with binutils 2.32+ as
otherwise the .notes section gets emitted with broken alignment.

m/t/launch: RunMicroVM is broken if SerialPort is not set with newer
QEMU versions because fcntl(2) fails to interact with a broken file
descriptor. This is due to a confusion between nil interfaces and
interfaces containing a nil pointer causing Go to improperly pass the
file descriptor. Changing the type of SerialPort to the actual
interface resolves the issue.

Change-Id: I03a8cbf4f80a7363794dad1ff62ccb57e778cac3
Reviewed-on: https://review.monogon.dev/c/monogon/+/529
Reviewed-by: Leopold Schabel <leo@nexantic.com>
diff --git a/metropolis/test/launch/launch.go b/metropolis/test/launch/launch.go
index 4a4c803..219e787 100644
--- a/metropolis/test/launch/launch.go
+++ b/metropolis/test/launch/launch.go
@@ -22,6 +22,7 @@
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"net"
 	"os"
 	"os/exec"
@@ -148,7 +149,7 @@
 	// port of the machine It can be set to an existing file descriptor (like
 	// os.Stdout/os.Stderr) or you can use NewSocketPair() to get one end to talk to
 	// from Go.
-	SerialPort *os.File
+	SerialPort io.Writer
 
 	// ExtraChardevs can be used similar to SerialPort, but can contain an arbitrary
 	// number of additional serial ports