This adds a mechanism for the unittests to be run with the TreadleBackend

This mechanism is not enabled and should not change the behavior of existing tests
A following PR will deliver a switch that will allow changing the backend.
The reasons for this PR
- Treadle tests run much faster, enabling quicker debugging and CI cycles
- This will help ensure fidelity of Treadle to the Verilator backend

A few tests are marked as verilator only due to black box limitations

Change treadle to a direct dependency

I tried to make it a test only dependency but the TesterDriver sits in src/main requiring that
regular compile have access to treadle

Oops, made treadle the default

A number of changes in response to @ducky64 review
- made backend check clearer and add error handling for multiple backends specified
- Fixed duplicate TargetDirAnnotation uses in Treadle backend
- Cleaned up BlackBox test formatting
- Undid unnecessary debugging changes from Counter
- Undid .gitignore change, that should be on another PR

A number of changes in response to @ducky64 review
- Undid debugging changes made to BitWiseOps

1 files changed, 1 insertions, 1 deletions

diff --git a/src/test/scala/chiselTests/MultiClockSpec.scala b/src/test/scala/chiselTests/MultiClockSpec.scala
index 1a71570d..8b7fddb0 100644
--- a/src/test/scala/chiselTests/MultiClockSpec.scala
+++ b/src/test/scala/chiselTests/MultiClockSpec.scala
@@ -120,7 +120,7 @@ class MultiClockSpec extends ChiselFlatSpec {
   }
 
   it should "scope ports of memories" in {
-    assertTesterPasses(new MultiClockMemTest)
+    assertTesterPasses(new MultiClockMemTest, annotations = TesterDriver.verilatorOnly)
   }
 
   it should "return like a normal Scala block" in {