all: move -panic=trap support to the compiler/runtime

Support for `-panic=trap` was previously a pass in the optimization
pipeline. This change moves it to the compiler and runtime, which in my
opinion is a much better place.

As a side effect, it also fixes
https://github.com/tinygo-org/tinygo/issues/4161 by trapping inside
runtime.runtimePanicAt and not just runtime.runtimePanic.

This change also adds a test for the list of imported functions. This is
a more generic test where it's easy to add more tests for WebAssembly
file properties, such as exported functions.

transform/optimizer.go

@@ -40,10 +40,6 @@ func Optimize(mod llvm.Module, config *compileopts.Config) []error {
 		fn.SetLinkage(llvm.ExternalLinkage)
 	}
 
-	if config.PanicStrategy() == "trap" {
-		ReplacePanicsWithTrap(mod) // -panic=trap
-	}
-
 	// run a check of all of our code
 	if config.VerifyIR() {
 		errs := ircheck.Module(mod)