Add ijar to third_party and use it for generating .jar.toc files in GN

It's much faster than using javap (what we currently do):

With javap, building chrome_java:
real    1m17.162s
user    7m46.230s
sys     0m42.836s

With ijar, building chrome_java:
real    0m56.446s
user    5m38.761s
sys     0m26.006s


Review URL:

Cr-Commit-Position: refs/heads/master@{#347208}
GitOrigin-RevId: 77614d453e6324c9da3e12b93b4c19800cbe09a9
13 files changed