tests: run many tests in $TESTTMP/repo instead of $TESTTMP
This is useful so we can store other files in $TESTTMP
(in particular tests that use docket files (nodemap, dirstate-v2) keep
file uids in $TESTTMP/UID)
#require symlink
https://bz.mercurial-scm.org/1438
$ hg init repo
$ cd repo
$ ln -s foo link
$ hg add link
$ hg ci -mbad link
$ hg rm link
$ hg ci -mok
$ hg diff -g -r 0:1 > bad.patch
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg import --no-commit bad.patch
applying bad.patch
$ hg status
R link
? bad.patch