Update libm to fix floating point panics for debug no_std builds #240
Description
On the README there's this note:
Floating point operations in no_std use libm, which sometimes panics in debug mode (rust-lang/libm#4). So make sure to either use release builds or avoid WASM with floating point operations, for example by using deny_floating_point.
The linked issue(rust-lang/libm#4) was resolved a while back, so wasmi can update the version of libm to fix the problematic behavior described in the above quote.