Rich Kadel 51268d2735 Check for LLVM 11+ when using -Z instrument-coverage
* `rustc` should now compile under LLVM 9 or 10
* Compiler generates an error if `-Z instrument-coverage` is specified
  but LLVM version is less than 11
* Coverage tests that require `-Z instrument-coverage` and run codegen
  should be skipped if LLVM version is less than 11
2020-11-24 11:50:24 -08:00
..