[tests] Remove dead code. (#21422)

This logic was intented to zip up the .NET unit tests to run them on Windows,
but in the end we went with a different approach that doesn't require zipping.

tests/Makefile

@@ -240,14 +240,6 @@ else
 	@echo Not enabled
 endif
 
-ifdef INCLUDE_DOTNET
-dotnet-test-package.7z:
-	./package-dotnet-tests.sh
-else
-dotnet-test-package.7z:
-	@echo Not enabled
-endif
-
 #XI
 ifdef INCLUDE_IOS
 wrench-mtouch:

tests/package-dotnet-tests.sh

@@ -1,45 +0,0 @@
-#!/bin/bash -ex
-
-cd "$(dirname "${BASH_SOURCE[0]}")"
-
-# Clone files instead of copying them on APFS file systems. Much faster.
-CP="cp"
-if df -t apfs / >/dev/null 2>&1; then
-	CP="cp -c"
-fi
-
-#git clean -xfdq
-
-rm -Rf "$(pwd)/dotnet-test-package"
-DIR=$(pwd)/dotnet-test-package/xamarin-macios
-ZIP=$DIR.7z
-mkdir -p $DIR
-mkdir -p $DIR/tests/dotnet/UnitTests/bin/Debug/net5.0/
-mkdir -p $DIR/.git
-
-make -j8
-make -C dotnet/UnitTests publish
-
-$CP -r dotnet $DIR/tests/
-rm -Rf $DIR/tests/dotnet/packages
-
-# Various files to make 'make' work
-$CP -p ../Make.config $DIR
-$CP -p ../Make.versions $DIR
-$CP -p ../Make.config $DIR
-mkdir -p $DIR/mk
-$CP -p ../Make.config $DIR
-$CP -p ../mk/subdirs.mk $DIR/mk
-$CP -p ../mk/rules.mk $DIR/mk
-$CP -p ../mk/quiet.mk $DIR/mk
-$CP -p ../mk/mono.mk "$DIR/mk"
-
-# Files to make the unit tests run
-$CP -p ../global.json $DIR
-$CP -p ../NuGet.config $DIR
-$CP -p test.config $DIR/tests
-
-# Zip it all up
-rm -f dotnet-test-package.7z
-cd dotnet-test-package
-7z a ../dotnet-test-package.7z *