Add a new --order option to choose between available test orders:
the default "smart" order, predictable "lexical" order or "random"
order. Default to using lexical order and one job in the lit test
suite.
Differential Revision: https://reviews.llvm.org/D107695
All of these depend on the order of tests, so if one runs them twice,
the tests within them will naturally be reordered
using the previous run times, which breaks them.
Move progress display to separate file. Simplify some code paths.
Decouple from other components via progress callback. Remove unused
`_Display` class.
Reviewed By: serge-sans-paille
Differential Revision: https://reviews.llvm.org/D68525
llvm-svn: 374194
