6896978: README: Updates to openjdk README-builds.html
6903517: README: OpenJDK additions needed - cygwin issues
Reviewed-by: dholmes

Reviewed-by: cl

Reviewed-by: darcy

Summary: Report the build times at end of a jdkroot build.
Reviewed-by: ohair

Reviewed-by: darcy, katleman, jjg

Reviewed-by: billyh, jqzuo

Reviewed-by: rinaldo

Reviewed-by: katleman, cl, igor, trims

Reviewed-by: ohair, igor

Reviewed-by: prr

Reviewed-by: robilad