[dmd-internals] auto-tester changes

[Brad Roberts via dmd-internals]

I upgraded the host 'macair' tonight from osx 10.9 to 10.11 and from gcc 
4.x to clang 7.0.2 in the process.  It looks like the 64_32 cross build 
is failing in one of the c++ abi compatibility tests now.

https://auto-tester.puremagic.com/show-run.ghtml?runid=99824&projectid=1

The 64_64 build passes the build/test cycle just fine, so it's a 32bit 
specific issue.  For now, I've disabled 32 bit builds on that host. 
I'll gather more detailed info for a bug report tomorrow (after looking 
to see if someone else hasn't already reported it).

Also, since I had a bit of time to kill while it was downloading the os 
updates, I decided to add a graph I've been wanting to see for a long 
time, the distribution of the age of open pull requests.  It's the top 
graph on the "Project Graphs" tab of each auto-tester project.

https://auto-tester.puremagic.com/chart.ghtml?projectid=1

Later,
Brad