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/transform_test.go

@@ -137,6 +137,7 @@ func compileGoFileForTesting(t *testing.T, filename string) llvm.Module {
 		Scheduler:          config.Scheduler(),
 		AutomaticStackSize: config.AutomaticStackSize(),
 		Debug:              true,
+		PanicStrategy:      config.PanicStrategy(),
 	}
 	machine, err := compiler.NewTargetMachine(compilerConfig)
 	if err != nil {