[NativeAOT-LLVM] Update llvm to 18.1.3 and emscripten to 3.1.54

[yowl]

Updates the version of LLVM and emscripten.

depends #2591

Moving emscripten later than 3.1.54 causes C/C++ version standard problems, i.e. need to go from gnu99 to c11:

E.g.

C:/github/runtimelab/src/native/libs/System.Native/pal_networking.c(171,1): error GB0A439F3: '_Static_assert' is incompatible with C standards before C11 [-Wer
ror,-Wpre-c11-compat] [C:\github\runtimelab\src\native\libs\build-native.proj]

[yowl]

Will squash once the May merge is in.

[yowl]

cc @dotnet/nativeaot-llvm

[jkotas]

Thanks