net/http: TestTLSHandshakeTimeout failure on solaris-amd64-oraclerel builder

[bcmills]

--- FAIL: TestTLSHandshakeTimeout (10.17s)
    serve_test.go:3636: Timeout expired after 10s
FAIL
FAIL	net/http	15.953s

2020-02-19T22:59:15-c4c73ce/solaris-amd64-oraclerel

This looks to me like a too-short hard-coded timeout.

CC @bradfitz

[gopherbot]

Change https://golang.org/cl/225977 mentions this issue: net/http: remove arbitrary timeouts from TestIdentityResponse and TestTLSHandshakeTimeout

[gopherbot]

Change https://golang.org/cl/226137 mentions this issue: net/http: remove another arbitrary timeout in TestTLSHandshakeTimeout