Use quiche string libraries in third_party/quic/test_tools
gfe-relnote: n/a, no functional change
PiperOrigin-RevId: 285009487
Change-Id: Ib5df01e93b8567c062cac8e5469e1ff86161445f
QUICHE (QUIC, Http/2, Etc) is Google‘s implementation of QUIC and related protocols. It powers Chromium as well as Google’s QUIC servers and some other projects.