lib: bootstrap should not have RegExp side effects

[bnoordhuis]

$ ./out/Release/node -p 'RegExp.$_' | head -10
{ 'target_defaults': { 'cflags': [],
                       'default_configuration': 'Release',
                       'defines': [],
                       'include_dirs': [],
                       'libraries': []},
  'variables': { 'asan': 0,
                 'coverage': 'false',
                 'debug_http2': 'false',
                 'debug_nghttp2': 'false',
                 'force_dynamic_crt': 0,

(Due to fixing up config.gypi in setupConfig() in lib/internal/process.js.)

[gireeshpunathil]

@bnoordhuis - close-able as #19140 has landed?

[bnoordhuis]

Yep, closing.