Revert "test_environment: simplify SINGULARITY_BIND handling"

This reverts commit 5b9f472.

Author: mr-c

tests/test_environment.py

@@ -159,11 +159,14 @@ def PWD(v: str, env: Env) -> bool:
         if version >= Version("3.6"):
             sing_vars["SINGULARITY_COMMAND"] = "exec"
         if version >= Version("3.7"):
+            if version > Version("3.9"):
+                sing_vars["SINGULARITY_BIND"] = ""
+            else:
 
-            def BIND(v: str, env: Env) -> bool:
-                return True
+                def BIND(v: str, env: Env) -> bool:
+                    return v.startswith(tmp_prefix) and v.endswith(":/tmp")
 
-            sing_vars["SINGULARITY_BIND"] = BIND
+                sing_vars["SINGULARITY_BIND"] = BIND
         if version >= Version("3.10"):
             sing_vars["SINGULARITY_COMMAND"] = "run"
             sing_vars["SINGULARITY_NO_EVAL"] = None