No deploy nullptrs (except deprecated)

[notlesh]

This is the same as #427 except that the OS still uses cast(0, felt*) during deprecated deploys.

The changes to the OS are effectively:

diff --git a/src/starkware/starknet/core/os/execution/deprecated_execute_entry_point.cairo b/src/starkware/starknet/core/os/execution/deprecated_execute_entry_point.cairo
index d147c23f7b..e329f5855d 100644
--- a/src/starkware/starknet/core/os/execution/deprecated_execute_entry_point.cairo
+++ b/src/starkware/starknet/core/os/execution/deprecated_execute_entry_point.cairo
@@ -128,7 +128,7 @@ func deprecated_execute_entry_point{
         // Assert that there is no call data in the case of NOP entry point.
         assert execution_context.calldata_size = 0;
         %{ execution_helper.skip_call() %}
-        return (retdata_size=0, retdata=cast(0, felt*));
+        return (retdata_size=0, retdata=cast(nondet %{ segments.add() %}, felt*));
     }

     local range_check_ptr = range_check_ptr;

diff --git a/src/starkware/starknet/core/os/execution/execute_entry_point.cairo b/src/starkware/starknet/core/os/execution/execute_entry_point.cairo
index ef2ca40441..7b32e759af 100644
--- a/src/starkware/starknet/core/os/execution/execute_entry_point.cairo
+++ b/src/starkware/starknet/core/os/execution/execute_entry_point.cairo
@@ -171,7 +171,7 @@ func execute_entry_point{
         // Assert that there is no call data in the case of NOP entry point.
         assert execution_context.calldata_size = 0;
         %{ execution_helper.skip_call() %}
-        return (retdata_size=0, retdata=cast(0, felt*));
+        return (retdata_size=0, retdata=cast(nondet %{ segments.add() %}, felt*));
     }

     let entry_point_offset = compiled_class_entry_point.offset;

[notlesh]

Closing as this issue was addressed in cairo-vm