tests: fix timer scaling in wait-on-file

When using the default test timeouts, wait-on-file would not wait for $n
seconds, but $n/100 seconds. This resulted in easy timeouts on even
moderately busy fast machines. Fix the scaling to apply in all cases.
Adjust the stepping slightly to be nicer to systems with the historic
100Hz time base to ensure that the scheduler actually switches to a
different process and gives them time to work.

Differential Revision: https://phab.mercurial-scm.org/D8505

tests/testlib/wait-on-file

@@ -11,9 +11,12 b' fi'
 
 timer="$1"
 
-# if the test timeout have been extended, explicitly extend the provided timer
+# Scale the timeout to match the sleep steps below, i.e. 1/0.02.
+timer=$(( 50 * $timer ))
+# If the test timeout have been extended, also scale the timer relative
+# to the normal timing.
 if [ "$HGTEST_TIMEOUT_DEFAULT" -lt "$HGTEST_TIMEOUT" ]; then
-    timer=$(( ( 100 * $timer * $HGTEST_TIMEOUT) / $HGTEST_TIMEOUT_DEFAULT ))
+    timer=$(( ( $timer * $HGTEST_TIMEOUT) / $HGTEST_TIMEOUT_DEFAULT ))
 fi
 
 wait_on="$2"
@@ -28,7 +31,7 b' if [ -n "$create" ]; then'
 fi
 while [ "$timer" -gt 0 ] && [ ! -f "$wait_on" ]; do
     timer=$(( $timer - 1))
-    sleep 0.01
+    sleep 0.02
 done
 if [ "$timer" -le 0 ]; then
     echo "file not created after $1 seconds: $wait_on" >&2