Cleanup #22182 (#22205)

* Turns compute_units_consumed of ProcessInstructionResult into a &mut parameter.

* Removes second nesting level from test_process_instruction_compute_budget().

* Makes test_process_cross_program and test_native_invoke symmetric.

* Unifies test_process_cross_program(), test_native_invoke() and test_process_instruction_compute_budget() into test_process_instruction().

program-test/src/lib.rs

@@ -276,14 +276,15 @@ impl solana_sdk::program_stubs::SyscallStubs for SyscallStubs {
             }
         }
 
+        let mut compute_units_consumed = 0;
         invoke_context
             .process_instruction(
                 &instruction.data,
                 &instruction_accounts,
                 Some(&caller_write_privileges),
                 &program_indices,
+                &mut compute_units_consumed,
             )
-            .result
             .map_err(|err| ProgramError::try_from(err).unwrap_or_else(|err| panic!("{}", err)))?;
 
         // Copy invoke_context accounts modifications into caller's account_info