tests: use 'do sleep 0' instead of 'do true', also on first line of command

2cd44a791e66 established that '... do true ...' shouldn't be used, but that was
only enforced on continued lines.

contrib/check-code.py

@@ -75,6 +75,7 @@ testpats = [
     (r'^alias\b.*=', "don't use alias, use a function"),
     (r'if\s*!', "don't use '!' to negate exit status"),
     (r'/dev/u?random', "don't use entropy, use /dev/zero"),
+    (r'do\s*true;\s*done', "don't use true as loop body, use sleep 0"),
   ],
   # warnings
   []
@@ -98,8 +99,6 @@ utestpats = [
     (uprefix + r'set -e', "don't use set -e"),
     (uprefix + r'\s', "don't indent commands, use > for continued lines"),
     (uprefixc + r'( *)\t', "don't use tabs to indent"),
-    (uprefixc + r'.*do\s*true;\s*done',
-     "don't use true as loop body, use sleep 0"),
   ],
   # warnings
   []

tests/test-bad-pull.t

@@ -20,7 +20,7 @@
 
   $ python dumb.py 2> log &
   $ P=$!
-  $ while [ ! -f listening ]; do true; done
+  $ while [ ! -f listening ]; do sleep 0; done
   $ hg clone http://localhost:$HGPORT/foo copy2
   abort: HTTP Error 404: * (glob)
   [255]

tests/test-hgweb-raw.t

@@ -20,7 +20,7 @@ Test raw style of hgweb
   $ cat hg.pid >> $DAEMON_PIDS
   $ ("$TESTDIR/get-with-headers.py" localhost:$HGPORT '/?f=a23bf1310f6e;file=sub/some%20%22text%22.txt;style=raw' content-type content-length content-disposition) >getoutput.txt
 
-  $ while kill `cat hg.pid` 2>/dev/null; do true; done
+  $ while kill `cat hg.pid` 2>/dev/null; do sleep 0; done
 
   $ cat getoutput.txt
   200 Script output follows
@@ -41,7 +41,7 @@ Test raw style of hgweb
 
   $ cat hg.pid >> $DAEMON_PIDS
   $ ("$TESTDIR/get-with-headers.py" localhost:$HGPORT '/?f=a23bf1310f6e;file=sub/some%20%22text%22.txt;style=raw' content-type content-length content-disposition) >getoutput.txt
-  $ while kill `cat hg.pid` 2>/dev/null; do true; done
+  $ while kill `cat hg.pid` 2>/dev/null; do sleep 0; done
 
   $ cat getoutput.txt
   200 Script output follows

tests/test-http-proxy.t

@@ -9,7 +9,7 @@
   $ cat hg.pid >> $DAEMON_PIDS
   $ cd ..
   $ "$TESTDIR/tinyproxy.py" $HGPORT1 localhost >proxy.log 2>&1 </dev/null &
-  $ while [ ! -f proxy.pid ]; do true; done
+  $ while [ ! -f proxy.pid ]; do sleep 0; done
   $ cat proxy.pid >> $DAEMON_PIDS
 
 url for proxy, stream

tests/test-https.t

@@ -233,12 +233,12 @@ Fingerprints
   $ hg -R copy-pull id https://127.0.0.1:$HGPORT/
   5fed3813f7f5
 
-  $ while kill `cat hg1.pid` 2>/dev/null; do true; done
+  $ while kill `cat hg1.pid` 2>/dev/null; do sleep 0; done
 
 Prepare for connecting through proxy
 
   $ "$TESTDIR/tinyproxy.py" $HGPORT1 localhost >proxy.log </dev/null 2>&1 &
-  $ while [ ! -f proxy.pid ]; do true; done
+  $ while [ ! -f proxy.pid ]; do sleep 0; done
   $ cat proxy.pid >> $DAEMON_PIDS
 
   $ echo "[http_proxy]" >> copy-pull/.hg/hgrc