Reorganize test dir to ensure test of installed pkg

tests/lib/sv_line_anchor.py

@@ -0,0 +1,10 @@
+from jinja2_simple_tags import StandaloneTag
+
+class SVLineAnchor(StandaloneTag):
+    """
+    Define a custom Jinja tag that emits a SystemVerilog `line directive so that
+    assertion messages can get properly back-annotated
+    """
+    tags = {"sv_line_anchor"}
+    def render(self):
+        return f'`line {self.lineno + 1} "{self.template}" 0'