Fix #12405 - workaround for fragile jline3 console detection in REPL

[philwalk]

This fixes 2 issues:

1. add workaround for console detection issues (see jline3 console detection is fragile in Windows cmd.exe, cygwin, msys, and mingw environments. #12405)
2. refine the handling of JNA classpath variable for various combinations of ConEmu and shell

In Windows Console, these REPL combinations are made fully functional:

MINGW64_NT-10.0-19042 d5 3.1.7-340.x86_64 2020-11-08 12:32 UTC x86_64 Msys
MINGW32_NT-10.0-19042 d5 3.1.7-340.x86_64 2020-11-08 12:32 UTC x86_64 Msys
MSYS_NT-10.0-19042 d5 3.1.7-340.x86_64 2020-11-08 12:32 UTC x86_64 Msys
CYGWIN_NT-10.0 d5 3.2.0(0.340/5/3) 2021-03-29 08:42 x86_64 Cygwin

In ConEmu, these are fully functional:

MINGW64_NT-10.0-19042 d5 3.1.7-340.x86_64 2020-10-23 13:08 UTC x86_64 Msys
CYGWIN_NT-10.0 d5 3.2.0(0.340/5/3) 2021-03-29 08:42 x86_64 Cygwin

In mintty, cygwin64 is fully functional

CYGWIN_NT-10.0 d5 3.2.0(0.340/5/3) 2021-03-29 08:42 x86_64 Cygwin

Some other combinations are partially functional (arrow keys don't work, might need to set TERM=dumb).

[liufengyun]

LGTM, thanks @philwalk 🎉