Skip t9020 with MSys2

POSIX-to-Windows path mangling would make it fail.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

t/t9020-remote-svn.sh

@@ -12,6 +12,12 @@ then
 	test_done
 fi
 
+if test_have_prereq MINGW
+then
+	skip_all='skipping remote-svn tests for lack of POSIX'
+	test_done
+fi
+
 # Override svnrdump with our simulator
 PATH="$HOME:$PATH"
 export PATH PYTHON_PATH GIT_BUILD_DIR