tests: stabilize test-amend.t on Windows
If $TESTTMP isn't quoted in this context, it ends up like
`C:Temphgtests.pikkoxchild1test-amend.t-obsstore-off`.
Differential Revision: https://phab.mercurial-scm.org/D8144
--- a/tests/test-amend.t Mon Feb 24 13:28:49 2020 +0900
+++ b/tests/test-amend.t Mon Feb 24 16:33:10 2020 -0500
@@ -487,7 +487,7 @@
$ echo beta >> foo
$ cat > $TESTTMP/touchy_editor.sh <<EOF
> sleep 1
- > echo delta >> $TESTTMP/modify-during-amend/foo
+ > echo delta >> "$TESTTMP/modify-during-amend/foo"
> sleep 1
> echo hi > "\$1"
> sleep 1