test-histedit: $TESTTMP quoting fixes for Windows
Without this, C:\path\to\test is converted into C:pathtotest.
Since $TESTTMP appears in output, seems to work in some places without quotes,
and is also used within a larger quote block (see test-rebase-collapse.t, ~line
160), I'm not sure what a check-code rule would look like (or even if it is
feasible).
$ hg init
$ echo This is file a1 > a
$ hg add a
$ hg commit -m "commit #0"
$ ls
a
$ echo This is file b1 > b
$ hg add b
$ hg commit -m "commit #1"
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
B should disappear
$ ls
a