cgo: add support for #cgo noescape lines

Here is the proposal:
https://github.com/golang/go/issues/56378

They are documented here:
https://pkg.go.dev/cmd/cgo@master#hdr-Optimizing_calls_of_C_code

This would have been very useful to fix
https://github.com/tinygo-org/bluetooth/issues/176 in a nice way. That
bug is now fixed in a different way using a wrapper function, but once
this new noescape pragma gets included in TinyGo we could remove the
workaround and use `#cgo noescape` instead.

cgo/testdata/symbols.out.go

@@ -75,5 +75,10 @@ func C.staticfunc!symbols.go(x C.int)
 
 var C.staticfunc!symbols.go$funcaddr unsafe.Pointer
 
+//export notEscapingFunction
+//go:noescape
+func C.notEscapingFunction(a *C.int)
+
+var C.notEscapingFunction$funcaddr unsafe.Pointer
 //go:extern someValue
 var C.someValue C.int