Build compiler with --noNimblePath (#20168)

- Fixes https://github.com/nim-lang/Nim/issues/18840

koch.nim

@@ -332,9 +332,9 @@ proc boot(args: string) =
     # in order to use less memory, we split the build into two steps:
     # --compileOnly produces a $project.json file and does not run GCC/Clang.
     # jsonbuild then uses the $project.json file to build the Nim binary.
-    exec "$# $# $# --nimcache:$# $# --compileOnly compiler" / "nim.nim" %
+    exec "$# $# $# --nimcache:$# $# --noNimblePath --compileOnly compiler" / "nim.nim" %
       [nimi, bootOptions, extraOption, smartNimcache, args]
-    exec "$# jsonscript --nimcache:$# $# compiler" / "nim.nim" %
+    exec "$# jsonscript --noNimblePath --nimcache:$# $# compiler" / "nim.nim" %
       [nimi, smartNimcache, args]
 
     if sameFileContent(output, i.thVersion):