Resolve libcall relocations for older CPUs (#5567)

* Resolve libcall relocations for older CPUs

Long ago Wasmtime used to have logic for resolving relocations
post-compilation for libcalls which I ended up removing during
refactorings last year. As #5563 points out, however, it's possible to
get Wasmtime to panic by disabling SSE features which forces Cranelift
to use libcalls for some floating-point operations instead. Note that
this also requires disabling SIMD because SIMD support has a baseline of
SSE 4.2.

This commit pulls back the old implementations of various libcalls and
reimplements logic necessary to have them work on CPUs without SSE 4.2

Closes #5563

* Fix log message in `wast` support

* Fix offset listed in relocations

Be sure to factor in the offset of the function itself

* Review comments

crates/wast/src/wast.rs

@@ -363,7 +363,7 @@ impl<T> WastContext<T> {
             let sp = directive.span();
             if log::log_enabled!(log::Level::Debug) {
                 let (line, col) = sp.linecol_in(wast);
-                log::debug!("failed directive on {}:{}:{}", filename, line + 1, col);
+                log::debug!("running directive on {}:{}:{}", filename, line + 1, col);
             }
             self.run_directive(directive)
                 .map_err(|e| match e.downcast() {