regression: error evaluating JSON file: with koch boot

[timotheecour]

/cc @Clyybber @kaushalmodi

regression introduced in nim-lang#13606

Example

./koch boot -d:release -d:nimUseLinenoise --hints:off

Current Output

iteration: 1
bin/nim c  --skipUserCfg --skipParentCfg -d:release -d:nimUseLinenoise --hints:off --nimcache:nimcache/r_macosx_amd64 --compileOnly compiler/nim.nim
/Users/timothee/git_clone/nim/Nim_temp/compiler/scriptconfig.nim(17, 3) Warning: imported and not used: 'lineinfos' [UnusedImport]
/Users/timothee/git_clone/nim/Nim_temp/compiler/scriptconfig.nim(15, 48) Warning: imported and not used: 'msgs' [UnusedImport]
bin/nim jsonscript -d:release -d:nimUseLinenoise --hints:off --nimcache:nimcache/r_macosx_amd64 compiler/nim.nim
iteration: 2
compiler/nim1 c  -d:release -d:nimUseLinenoise --hints:off --nimcache:nimcache/r_macosx_amd64 --compileOnly compiler/nim.nim
/Users/timothee/git_clone/nim/Nim_temp/compiler/scriptconfig.nim(17, 3) Warning: imported and not used: 'lineinfos' [UnusedImport]
/Users/timothee/git_clone/nim/Nim_temp/compiler/scriptconfig.nim(15, 48) Warning: imported and not used: 'msgs' [UnusedImport]
compiler/nim1 jsonscript -d:release -d:nimUseLinenoise --hints:off --nimcache:nimcache/r_macosx_amd64 compiler/nim.nim

caught exception:n/Users/timothee/git_clone/nim/Nim_temp/nimcache/r_macosx_amd64/nim.json(2, 1) Error: { expected
stacktrace:
parsejson.nim(522)       raiseParseErr
error evaluating JSON file: /Users/timothee/git_clone/nim/Nim_temp/nimcache/r_macosx_amd64/nim.json
FAILURE

Expected Output

works

Additional Information

regression introduced in nim-lang#13606

[timotheecour]

=> nim-lang#13633