Added architecture linker specific flags to toolchains

[perseoGI]

Changelog: Feature: New linker flags autodetected by conan based on profile architecture.
Docs: omit

In #18432 native asmjs architecture support was introduced.
To enable asmjs code generation the -sWASM=0 flag needs to be passed to the emscripten linker.

That flag was added in architecture_flag without noticing that those flags were being passed to both compiler and linker across all toolchains.
This was causing the compiler to throw warnings as this flag is only understood by the linker:

em++: warning: linker setting ignored during compilation: 'WASM' [-Wunused-command-line-argument]

Having a compilation warning is not desirable as a compilation with warning as errors will result in a build failure:

em++: error: linker setting ignored during compilation: 'WASM' [-Wunused-command-line-argument] [-Werror]

This PR aims to address this issue by creating a new architecture_link_flags which will return the required flags only for the linker based on the profile architecture.

This function will be called by several toolchains which will bypass the result to the final linker by setting LD_FLAGS.

Tests

The current test_emcc test suite already tests this new functionality added.

[memsharded]

Just a minor issue in the CMake integration.

It will be necessary to add some tests (can be integration, no need to be functional)