Update README.chromium to reflect whether a tool is shipped or not

Mark tools that are only used for testing as NOT_SHIPPED. Also fix bintree's license (MIT License -> MIT) and fix the name & short name of libc++-static.

BUG=499582

Review URL: https://codereview.chromium.org/1532203002

Cr-Original-Commit-Position: refs/heads/master@{#369150}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 6175da8042f3a0aa574f0da25e87be342625e603