[compiler-rt][asan][win] Intercept exceptions for i686 MinGW

The i686-w64-windows-gnu target does not use SEH (which MSVC uses),
but DWARF-2 exception handling or possibly sjlj depending on the
toolchain build options. On this target we have to actually intercept
functions in libc++ and libunwind which handles throwing exceptions.
This fixes the `TestCases/intercept-rethrow-exception.cpp` test.

The x86_64-w64-windows-gnu target already works because it uses SEH
which is handled by intercepting RaiseException, so this change does not
affect x86_64.

Depends on https://reviews.llvm.org/D148990

Differential Revision: https://reviews.llvm.org/D148991