fix: add back bin/node-gyp-bin/node-gyp files

This was an unintended breaking change as part of #6554. The `node-gyp`
bin files are not used by the CLI directly but they are relied on by
other tooling. This change is only intended to land on the v9 release
line.

This partially reverts commit 3a7378d.

bin/node-gyp-bin/node-gyp

@@ -0,0 +1,6 @@
+#!/usr/bin/env sh
+if [ "x$npm_config_node_gyp" = "x" ]; then
+  node "`dirname "$0"`/../../node_modules/node-gyp/bin/node-gyp.js" "$@"
+else
+  "$npm_config_node_gyp" "$@"
+fi

bin/node-gyp-bin/node-gyp.cmd

@@ -0,0 +1,5 @@
+if not defined npm_config_node_gyp (
+  node "%~dp0\..\..\node_modules\node-gyp\bin\node-gyp.js" %*
+) else (
+  node "%npm_config_node_gyp%" %*
+)