build: fix makefile script on windows

On Windows there is a program "find.exe" located in
C:\Windows\System32, which is usually in the PATH before
MSYS version of that program (required for running makefile).
The Windows version of the program uses different CLI syntax,
which results in errors like

  "File not found - *node_modules*"

This commit specifies the full path to the program, which is also
properly handled by MSYS on Windows.

PR-URL: https://github.com/nodejs/node/pull/33136


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>