tests: quote $PYTHON for py3 support on Windows

tests/test-convert-hg-svn.t

@@ -11,7 +11,7 b''
   > EOF
 
   $ SVNREPOPATH=`pwd`/svn-repo
-  $ SVNREPOURL="`$PYTHON $TESTDIR/svnurlof.py \"$SVNREPOPATH\"`"
+  $ SVNREPOURL="`"$PYTHON" $TESTDIR/svnurlof.py \"$SVNREPOPATH\"`"
 
   $ svnadmin create "$SVNREPOPATH"
   $ cat > "$SVNREPOPATH"/hooks/pre-revprop-change <<EOF

tests/test-convert-svn-move.t

@@ -8,7 +8,7 b''
   $ svnadmin create svn-repo
   $ svnadmin load -q svn-repo < "$TESTDIR/svn/move.svndump"
   $ SVNREPOPATH=`pwd`/svn-repo
-  $ SVNREPOURL="`$PYTHON $TESTDIR/svnurlof.py \"$SVNREPOPATH\"`"
+  $ SVNREPOURL="`"$PYTHON" $TESTDIR/svnurlof.py \"$SVNREPOPATH\"`"
 
 Convert trunk and branches
 

tests/test-convert-svn-source.t

@@ -13,7 +13,7 b''
 
   $ svnadmin create svn-repo
   $ SVNREPOPATH=`pwd`/svn-repo
-  $ SVNREPOURL="`$PYTHON $TESTDIR/svnurlof.py \"$SVNREPOPATH\"`"
+  $ SVNREPOURL="`"$PYTHON" $TESTDIR/svnurlof.py \"$SVNREPOPATH\"`"
   $ INVALIDREVISIONID=svn:x2147622-4a9f-4db4-a8d3-13562ff547b2/proj%20B/mytrunk@1
   $ VALIDREVISIONID=svn:a2147622-4a9f-4db4-a8d3-13562ff547b2/proj%20B/mytrunk/mytrunk@1
 

tests/test-mq-subrepo-svn.t

@@ -23,7 +23,7 b' handle svn subrepos safely'
   $ svnadmin create svn-repo-2499
 
   $ SVNREPOPATH=`pwd`/svn-repo-2499/project
-  $ SVNREPOURL="`$PYTHON $TESTDIR/svnurlof.py \"$SVNREPOPATH\"`"
+  $ SVNREPOURL="`"$PYTHON" $TESTDIR/svnurlof.py \"$SVNREPOPATH\"`"
 
   $ mkdir -p svn-project-2499/trunk
   $ svn import -qm 'init project' svn-project-2499 "$SVNREPOURL"

tests/test-subrepo-svn.t

@@ -1,7 +1,7 b''
 #require svn15
 
   $ SVNREPOPATH=`pwd`/svn-repo
-  $ SVNREPOURL="`$PYTHON $TESTDIR/svnurlof.py \"$SVNREPOPATH\"`"
+  $ SVNREPOURL="`"$PYTHON" $TESTDIR/svnurlof.py \"$SVNREPOPATH\"`"
 
   $ filter_svn_output () {
   >     egrep -v 'Committing|Transmitting|Updating|(^$)' || true