test-npm-install failing on freebsd 10/11

test-npm-install is currently failing consistently on freebsd11-x64 in CI.

Example failure: https://ci.nodejs.org/job/node-test-commit-freebsd/4792/nodes=freebsd11-x64/console

not ok 737 parallel/test-npm-install
# 
# assert.js:85
#   throw new assert.AssertionError({
#   ^
# AssertionError: npm install should run without an error
#     at ChildProcess.handleExit (/usr/home/iojs/build/workspace/node-test-commit-freebsd/nodes/freebsd11-x64/test/parallel/test-npm-install.js:48:10)
#     at ChildProcess.<anonymous> (/usr/home/iojs/build/workspace/node-test-commit-freebsd/nodes/freebsd11-x64/test/common.js:422:15)
#     at emitTwo (events.js:106:13)
#     at ChildProcess.emit (events.js:191:7)
#     at Process.ChildProcess._handle.onexit (internal/child_process.js:215:12)
  ---
  duration_ms: 2.45

/cc @thealphanerd @nodejs/testing