Find debug vim when sourcing single test file

[zewpo]

Problem: Sourcing single test scripts in DEBUG mode failed on MS-Win, because the scripts didn't find "..\vimd.exe"
Solution: Fix test script fallback, was hardcoded to '..\vim.exe', now the fallback checks for '..\vimd.exe' if '..\vim.exe' not found.

[zewpo]

Hopefully helpful to others as well.

[codecov]

Codecov Report

Merging #11525 (323bedf) into master (1d139a0) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #11525      +/-   ##
==========================================
- Coverage   81.88%   81.87%   -0.02%     
==========================================
  Files         162      162              
  Lines      189738   189738              
  Branches    43136    43136              
==========================================
- Hits       155371   155350      -21     
- Misses      21800    21826      +26     
+ Partials    12567    12562       -5     

Flag	Coverage Δ
huge-clang-none	82.73% <ø> (-0.02%)	⬇️
huge-gcc-none	54.67% <ø> (-0.01%)	⬇️
huge-gcc-testgui	53.10% <ø> (-0.01%)	⬇️
huge-gcc-unittests	0.29% <ø> (ø)
linux	82.50% <ø> (-0.01%)	⬇️
mingw-x64-HUGE	76.50% <ø> (-0.01%)	⬇️
mingw-x86-HUGE	77.26% <ø> (-0.03%)	⬇️
windows	78.14% <ø> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/beval.c	63.63% <0.00%> (-2.10%)	⬇️
src/os_win32.c	59.83% <0.00%> (-0.25%)	⬇️
src/message.c	78.72% <0.00%> (-0.23%)	⬇️
src/term.c	73.58% <0.00%> (-0.20%)	⬇️
src/spellfile.c	80.42% <0.00%> (-0.14%)	⬇️
src/search.c	85.10% <0.00%> (-0.09%)	⬇️
src/buffer.c	87.36% <0.00%> (-0.08%)	⬇️
src/regexp_nfa.c	89.74% <0.00%> (-0.07%)	⬇️
src/gui.c	72.85% <0.00%> (-0.05%)	⬇️
src/version.c	85.18% <0.00%> (ø)
... and 4 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.