[clang] [compiler-rt] [asan][windows] Eliminate the static asan runtime on windows (PR #81677)

[Charlie Barto via cfe-commits]

barcharcraz wrote:

> This is long description, but it does not explain WHY. Could you please add some explanation there?

Sure, the reason is to greatly simplify how asan works on windows, and to fix a bunch of bugs with asan+static CRT. Before this change there was a bunch of code that would redirect calls from various dlls into the executable if the asan runtime was statically linked, this code has never worked all that well, and it was a nightmare to fix. Additionally, statically linked DLLs didn't work with the previous scheme and weak symbols didn't work with /MD.

https://github.com/llvm/llvm-project/pull/81677