tests/test-wireproto-command-pushkey.t

setup: avoid attempting to invoke the system-wide hg.exe on Windows

On Windows, the executable in the current directory gets priority over anything
in $PATH (both for cmd.exe and MSYS).  That means, the former code was launching
the local hg.exe instead of the system-wide one, if it was previously built.  If
that failed, it then fell back to the local hg code, but run through python.exe.

I'm not sure what it is about ef7119cd4965, but that started throwing up a
messagebox that python37.dll couldn't be loaded.  (And indeed, python37 is not
in $PATH by default.)  Invoking the local hg via the current python avoids that.

  $ . $TESTDIR/wireprotohelpers.sh

  $ hg init server
  $ enablehttpv2 server
  $ cd server
  $ cat >> .hg/hgrc << EOF
  > [web]
  > push_ssl = false
  > allow-push = *
  > EOF
  $ hg debugdrawdag << EOF
  > C D
  > |/
  > B
  > |
  > A
  > EOF

  $ hg serve -p $HGPORT -d --pid-file hg.pid -E error.log
  $ cat hg.pid > $DAEMON_PIDS

pushkey for a bookmark works

  $ sendhttpv2peer << EOF
  > command pushkey
  >     namespace bookmarks
  >     key @
  >     old
  >     new 426bada5c67598ca65036d57d9e4b64b0c1ce7a0
  > EOF
  creating http peer for wire protocol version 2
  sending pushkey command
  response: True

  $ sendhttpv2peer << EOF
  > command listkeys
  >     namespace bookmarks
  > EOF
  creating http peer for wire protocol version 2
  sending listkeys command
  response: {
    b'@': b'426bada5c67598ca65036d57d9e4b64b0c1ce7a0'
  }

  $ cat error.log