tests: adjust quoting to keep Windows happy with recent $PYTHON change

I tried adding quotes to the $PYTHON variable, and also tried converting the
path from the current 'c:/Python/python.exe' form to '/c/python/python.exe', but
neither worked.  I'm not sure why one of these needs '\"' around the variable
and the other doesn't.

tests/test-bisect.t

@@ -463,12 +463,12 b' test bisecting command'
   $ chmod +x script.py
   $ hg bisect -r
   $ hg up -qr tip
-  $ hg bisect --command "$PYTHON \"$TESTTMP/script.py\" and some parameters"
+  $ hg bisect --command "\"$PYTHON\" \"$TESTTMP/script.py\" and some parameters"
   changeset 31:58c80a7c8a40: good
   abort: cannot bisect (no known bad revisions)
   [255]
   $ hg up -qr 0
-  $ hg bisect --command "$PYTHON \"$TESTTMP/script.py\" and some parameters"
+  $ hg bisect --command "\"$PYTHON\" \"$TESTTMP/script.py\" and some parameters"
   changeset 0:b99c7b9c8e11: bad
   changeset 15:e7fa0811edb0: good
   changeset 7:03750880c6b5: good

tests/test-import.t

@@ -64,7 +64,7 b' regardless of the commit message in the '
   added 1 changesets with 2 changes to 2 files
   updating to branch default
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
-  $ HGEDITOR=cat hg --config ui.patch='$PYTHON ../dummypatch.py' --cwd b import --edit ../exported-tip.patch
+  $ HGEDITOR=cat hg --config ui.patch="$PYTHON ../dummypatch.py" --cwd b import --edit ../exported-tip.patch
   applying ../exported-tip.patch
   second change