Insert ‘__gear_stack_end’ export in module if there is global ‘__stack_pointer’.
By default rust compilation into wasm creates global ‘__stack_pointer’, which
initialized by end of stack address. Unfortunately this global is not export.
By default ‘__stack_pointer’ has number 0 in globals, so if there is ‘__stack_pointer’ in
a name section, then we suppose that 0 global contains stack end addr, and insert an export
for this global. This export can be used in runtime to identify end of stack memory
and skip its uploading to storage.