[dvsim] Support for running pre-built SW tests

This PR adds support for running pre-built SW tests, with a few
optimizations:
- Removed `sw_dir` var from hjson - paths to SW tests relative to
`REPO_TOP` are to be indicated now with `sw_test` instead
- Renamed `sw_name` with `sw_test` instead
- Added `sw_test_is_prebuilt` flag to indicate that it is prebuilt
- Supporting updates in `sim.mk` to decide what to do based on the
above flag

Signed-off-by: Srikrishna Iyer <sriyer@google.com>
diff --git a/util/dvsim/Deploy.py b/util/dvsim/Deploy.py
index 0b1b2d6..0a53397 100644
--- a/util/dvsim/Deploy.py
+++ b/util/dvsim/Deploy.py
@@ -659,8 +659,8 @@
             "uvm_test": False,
             "uvm_test_seq": False,
             "run_opts": False,
-            "sw_dir": False,
-            "sw_name": False,
+            "sw_test": False,
+            "sw_test_is_prebuilt": False,
             "sw_build_device": False,
             "sw_build_dir": False,
             "run_dir": False,