[flang] Add support of sanitizers

[foxtran]

At the current moment, flang does not support:

• AddressSanitizer: https://godbolt.org/z/K5dKxYEnb
• LeakSanitizer: https://godbolt.org/z/s1nWfjYjh
• MemorySanitizer: https://godbolt.org/z/7674EK3a7
• UndefinedSanitizer: https://godbolt.org/z/nP6dPbMsE
• ThreadSanitizer: https://godbolt.org/z/GTKM3c5Tf

It would be nice to see their support with flang.

Hope I mentioned all available sanitizers in LLVM.

[foxtran]

If it requires only enabling of specific passes at LLVM codegen without a lot of touching of flang-frontend, I think I can implement flags to enable these features.

[llvmbot]

@llvm/issue-subscribers-flang-driver

Author: foxtran (foxtran)

At the current moment, flang does not support:

• AddressSanitizer: https://godbolt.org/z/K5dKxYEnb
• LeakSanitizer: https://godbolt.org/z/s1nWfjYjh
• MemorySanitizer: https://godbolt.org/z/7674EK3a7
• UndefinedSanitizer: https://godbolt.org/z/nP6dPbMsE
• ThreadSanitizer: https://godbolt.org/z/GTKM3c5Tf

It would be nice to see their support with flang.

Hope I mentioned all available sanitizers in LLVM.