TBR: devtools/v23-test/internal/test: escape test output for safer xml unmarshal.
TBR: devtools/v23-test/internal/test: escape test output for safer xml unmarshal.

This is mainly to fix this:

https://veyron.corp.google.com/jenkins/job/vanadium-go-test/409/ARCH=amd64,OS=darwin/testReport/junit/(root)/vanadium-go-test/Internal_Error/

PresubmitTest: none
Change-Id: If2c0351f467bcd3a95c4214289fec6bde5f55ea9

vanadium/go.devtools,vanadium/go.devtools,vanadium/go.devtools