[NativeAOT-LLVM] Runtime tests generate a significant number of warnings

[SingleAccretion]

Let's get at least HelloWasm clean, eleven warnings is too high a number to ignore.

Some of these are upstream problems we've picked up, but most should be actionable directly.

Current list of warnings:

1) Four MSB4011 - dotnet/runtime#70658

• Introduced by the manual inclusion of test_dependencies.*.props in Update Roslyn and use new step tracking API in incremental tests. runtime#63978. There are now two NuGet-related .props that are almost identical. The batched build does its own restore and so isn't affected.
• Upstream fix: Prevent tests from importing "normal" NuGet props/targets runtime#80573.

2) Two IL2070.

• One DAM will solve the problem.

3) clang++ : warning : argument unused during compilation: '-I C:\Users\Accretion\source\dotnet\emsdk\upstream\emscripten\cache\sysroot\include\SDL'.

• Emscripten adds SDL headers by default, and this triggers the warnings (since, presumably, nothing references the code in them). We can pass sUSE_SDL=0 ourselves to disable the default behavior, which could then go away once we update to emscripten which has Don't default to SDLv1 for un-versioned SDL includes emscripten-core/emscripten#18443.

4) EXEC : warning : undefined symbol: S_P_CoreLib_Internal_Runtime_CompilerHelpers_ThrowHelpers__ThrowBodyRemoved - appeared after the recent merge.

• We are using the wrong helper for tentative instance method stubs.

5) EXEC : warning : undefined symbol: dotnet_browser_entropy - good old dotnet_browser_entropy.

• Presumably there because System.Native references it.

6) emcc : warning : warnings in JS library compilation [-Wjs-compiler].

• Fallout from the undefined symbols warnings.

[SingleAccretion]

FYI @yowl