test: adjust test-push-race.t timeout's to overall test timeout
The generic `tests/testlib/wait-on-file` mechanism scale its timeout with the
value of `HGTEST_TIMEOUT`, the `delaypush.py` in `test-push-race.t` is not doing
this, and we have been seeing more and more timeout from loaded CI worker
lately.
Adding this timeout scaling should help with that.
$ hg init repo
$ cd repo
$ "$PYTHON" -c 'open("a", "wb").write(b"confuse str.splitlines\nembedded\rnewline\n")'
$ hg ci -Ama -d '1 0'
adding a
$ echo clean diff >> a
$ hg ci -mb -d '2 0'
$ hg diff -r0 -r1
diff -r 107ba6f817b5 -r 310ce7989cdc a
--- a/a Thu Jan 01 00:00:01 1970 +0000
+++ b/a Thu Jan 01 00:00:02 1970 +0000
@@ -1,2 +1,3 @@
confuse str.splitlines
embedded\r (no-eol) (esc)
newline
+clean diff