go 1.11.6/1.12 reject control characters in URLs already, causing test failures

[zeha]

go 1.11.6 and 1.12 contain this change: golang/go#29923

With 1.11.6, the tests for go-cleanhttp fail like this:

--- FAIL: TestPrintablePathCheckHandler (0.00s)
    --- FAIL: TestPrintablePathCheckHandler/invalid_carriage_return (0.00s)
        handlers_test.go:64: parse http://127.0.0.1:42665/invalid
: net/url: invalid control character in URL
    --- FAIL: TestPrintablePathCheckHandler/invalid_null (0.00s)
        handlers_test.go:64: parse http://127.0.0.1:40705/invalid: net/url: invalid control character in URL
    --- PASS: TestPrintablePathCheckHandler/valid_empty_error_status (0.00s)
    --- FAIL: TestPrintablePathCheckHandler/invalid_alternate_status (0.00s)
        handlers_test.go:64: parse http://127.0.0.1:45233/invalid
            : net/url: invalid control character in URL
    --- PASS: TestPrintablePathCheckHandler/valid_nil_input (0.00s)
    --- FAIL: TestPrintablePathCheckHandler/invalid_newline (0.00s)
        handlers_test.go:64: parse http://127.0.0.1:44825/invalid
            : net/url: invalid control character in URL

Thanks,
Chris