[clang] [clang][CodeGen] Emit improved memory effects and return status for AsmStmt (PR #110510)

[Bruno De Fraine via cfe-commits]

brunodf-snps wrote:

The intention is to enable LLVM to do more of the optimizations that GCC does around inline asm statements.

The following example demonstrates this: https://godbolt.org/z/53rzbjW7z
All of the test cases marked as "MISSED" are also optimized by LLVM with this patch, except for test2c and test2d.

https://github.com/llvm/llvm-project/pull/110510