Move ASAN tests to clang-7 (#62663)
Summary:
This should avoid following false positives:
```
[ RUN ] ProtoTest.Basic
/var/lib/jenkins/workspace/build/third_party/onnx/onnx/onnx_onnx_torch-ml.pb.h:7060:15: runtime error: member call on address 0x7fffffffdd80 which does not point to an object of type 'google::protobuf::MessageLite'
0x7fffffffdd80: note: object is of type 'onnx_torch::ModelProto'
00 00 00 00 b0 b9 05 ef ff 7f 00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00
^~~~~~~~~~~~~~~~~~~~~~~
vptr for 'onnx_torch::ModelProto'
UndefinedBehaviorSanitizer: undefined-behavior /var/lib/jenkins/workspace/build/third_party/onnx/onnx/onnx_onnx_torch-ml.pb.h:7060:15 in
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62663
Reviewed By: tktrungna
Differential Revision: D30076315
Pulled By: malfet
fbshipit-source-id: 7bfc2c4b417307195e3c3379e4874eaceb4f3134
