test float_roundtrip fails when using c guest

[ludfjig]

...but passes with rust guest. Why?

To replicate run
GUEST="c" cargo test -p hyperlight-host -- float_roundtrip --ignored
which fails. But
cargo test -p hyperlight-host -- float_roundtrip --ignored passes

[ludfjig]

The issue is that compiling rust with target x86_64-unknown-none does not use any floating point registers. However, compiling clang with target x86_64-unknown-none-elf does. There does not seem to be an easy way change this in clang