tests: choose the proper environment variable style for the platform Windows was printing out 'commit $HG_NODE' instead of the actual hash.

tests: fix another multi-statement hook for Windows The double quotes are necessary, otherwise it tries to pipe into a program named 'short'. An '&' could serve as a command separator on Windows instead of ';', but I don't see any obvious way to swap these depending on the platform. In this case though, there really wasn't a need for multiple statements.