Create Cronet's CTS for CronetEngine APIs

At the moment CronetCtsTestServer doesn't support QUIC and doesn't
report the negotiated protocol (i.e.,
UrlResponseInfo#getNegotiatedProtocol() will always return "unknown").
To circumenvent that, use "https://source.android.com" as target URL.

Test: atest CtsCronetTestCases
Change-Id: If5bf3d5e8f38675cddabba597db2d64e59cc5b60
1 file changed