fixup! t7800: configure $(pwd) for posix-paths on MINGW

We just did this differently, using the $PWD variable.

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

t/t7800-difftool.sh

@@ -10,14 +10,6 @@ Testing basic diff tool invocation
 
 . ./test-lib.sh
 
-if test_have_prereq MINGW
-then
-	# Avoid posix-to-windows path mangling
-	pwd () {
-		builtin pwd
-	}
-fi
-
 difftool_test_setup ()
 {
 	test_config diff.tool test-tool &&