tests: make removeemptydirs more portable

The behavior of pwd change from one system (i.e. default shell/sh) from one
system to another so we use fuzzy matching for the output we do not care and we
use narrower command call to highlight what we are trying to test here.

Differential Revision: https://phab.mercurial-scm.org/D11449

tests/test-removeemptydirs.t

@@ -1,5 +1,13 b''
 Tests for experimental.removeemptydirs
 
+  $ cat >> pwd.py << EOF
+  > import os
+  > try:
+  >     print(os.getcwd())
+  > except OSError:
+  >     print("<directory is no longer accessible>")
+  > EOF
+
   $ NO_RM=--config=experimental.removeemptydirs=0
   $ DO_RM=--config=experimental.removeemptydirs=1
   $ isdir() { if [ -d $1 ]; then echo yes; else echo no; fi }
@@ -132,8 +140,15 b' Windows is not affected'
   r1
   r2
   somedir
-  $ pwd
+#if windows
+  $ "$PYTHON" "$TESTTMP/pwd.py"
   $TESTTMP/hghistedit/somedir
+#else
+  $ echo ${PWD} # no-pwd-check
+  $TESTTMP/hghistedit/somedir
+  $ "$PYTHON" "$TESTTMP/pwd.py"
+  <directory is no longer accessible>
+#endif
   $ ls -1 $TESTTMP/hghistedit/somedir
   foo
   $ ls -1
@@ -142,6 +157,7 b' Windows is not affected'
 Get out of the doomed directory
 
   $ cd $TESTTMP/hghistedit
+  chdir: error retrieving current directory: getcwd: cannot access parent directories: $ENOENT$ (?)
   $ hg files --rev . | grep somedir/
   somedir/foo