[llvm] [llvm][llvm-lit] Add total time for each testsuite in JUnit XML output (PR #112230)

[Paul T Robinson via llvm-commits]

pogo59 wrote:

There are other "required" elements in that schema that we don't emit; should we be emitting them? Or are you just particularly interested in the per-testsuite statistic?

https://github.com/llvm/llvm-project/pull/112230