Currently emscripten is make assumptions about that memory layout,
assuming the stack is between `__data_end` and `__heap_base`:
af961ad5c4/system/lib/compiler-rt/stack_limits.S (L42-L61)
With this change we can be more precise:
https://github.com/emscripten-core/emscripten/pull/18057
Differential Revision: https://reviews.llvm.org/D135910