Remove ProcAttr models

Co-authored-by: Owen Mansel-Chan <62447351+owen-mc@users.noreply.github.com>

Author: egregius313

go/ql/lib/ext/os.model.yml

@@ -56,4 +56,3 @@ extensions:
       - ["os", "", False, "UserCacheDir", "", "", "ReturnValue[0]", "environment", "manual"]
       - ["os", "", False, "UserConfigDir", "", "", "ReturnValue[0]", "environment", "manual"]
       - ["os", "", False, "UserHomeDir", "", "", "ReturnValue[0]", "environment", "manual"]
-      - ["os", "ProcAttr", False, "Env", "", "", "", "environment", "manual"] # TODO: when sources can have access paths, use .ArrayElement

go/ql/lib/ext/syscall.model.yml

@@ -25,5 +25,4 @@ extensions:
       extensible: sourceModel
     data:
       - ["syscall", "", False, "Environ", "", "", "ReturnValue", "environment", "manual"]
-      - ["syscall", "", False, "Getenv", "", "", "ReturnValue[0]", "environment", "manual"]
-      - ["syscall", "ProcAttr", True, "Env", "", "", "", "environment", "manual"]
+      - ["syscall", "", False, "Getenv", "", "", "ReturnValue[0]", "environment", "manual"]