[Operator Versioning][Edge] Initialize upgrader thread safe (#70161)
Summary:
Upgrader should only be initialized once when runtime loads the first module. It no longer needs to initialized afterwards.
Previously, instead of using an atomic variable, the upgrader will be initialized depends on whether byteCodeFunctionWithOperator.function.get_code().operators_ is empty. If it's empty, it means the operator from the upgrader is not initialized yet. However, it's not thread safe. When multiple thread loads module together, it's possible that they all consider it's the first module. Use an atomic variable here to make sure it's thread safe.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/70161
ghstack-source-id: 146012642
Test Plan:
```
buck test mode/opt //papaya/integration/service/test/analytics/histogram:generic_histogram_system_test -- --exact 'papaya/integration/service/test/analytics/histogram:generic_histogram_system_test - SumHistogramSystemTest.test' --run-disabled
buck test mode/opt //caffe2/test/cpp/jit:jit
```
Reviewed By: iseeyuan
Differential Revision: D33220320
fbshipit-source-id: 10f2397c3b358d5a1d39a2ce25457e3fdb640d2c
