Limit exposure of implementation detail env vars to NodeJS

[Silic0nS0ldier]

These changes will hide env vars created by the launcher script, providing a cleaner environment.

Before:

{
  RUNFILES: '/[...].sh.runfiles',
  PWD: '[...]',
  NODE_REPOSITORY_ARGS: '--preserve-symlinks',
  TMPDIR: '/tmp',
  RUNFILES_MANIFEST_FILE: '/[...].sh.runfiles_manifest',
  BAZEL_NODE_RUNFILES_HELPER: '[...]',
  BAZEL_NODE_PATCH_REQUIRE: '[...]',
  BAZEL_TARGET: '[...]',
  NM_SYMLINKS: '/tmp/tmp.ocMuRFoTpU/nm-symlinks.json',
  SHLVL: '0',
  BAZEL_NODE_MODULES_ROOTS: '[...]',
  _RLOCATION_ISABS_PATTERN: '^/.*',
  BAZEL_PATCH_ROOTS: '[...]',
  PATH: '/nix/store/[...]/bin',
  BAZEL_WORKSPACE: '[...]',
  'BASH_FUNC_rlocation%%': '[...]',
  'BASH_FUNC_runfiles_export_envvars%%': '[...]',
  _: '[...]',
  __CF_USER_TEXT_ENCODING: '0x1F5:0:15'
}

After:

{
  NODE_REPOSITORY_ARGS: '--preserve-symlinks',
  PATH: '/nix/store/[...]/bin',
  TMPDIR: '/tmp',
  NM_SYMLINKS: '/tmp/tmp.UOHRoIIOwQ/nm-symlinks.json',
  // macOS thing
  __CF_USER_TEXT_ENCODING: '0x1F5:0:15',
  // For coverage support
  //NODE_V8_COVERAGE (tests only)
  // For NodeJS patcher
  RUNFILES_DIR: '[...]',
  RUNFILES: '[...]',
  BAZEL_PATCH_ROOTS: '[...]',
}

[christianscott]

LGTM

[Silic0nS0ldier]

Testing flushed out some issues which have now been fixed. Reduction isn't as significant now, but it is still less.

Also included now is a fix for pkg_npm which like all actions by default lacked PATH, meaning OS default tools were picked up.