Reflect refactor caused non-deterministic builds

[aykevl]

I found that TinyGo does not produce deterministic results anymore:

$ tinygo build -o test.hex -target=cortex-m-qemu ./testdata/calls.go && md5sum test.hex
e1bd69209b6fe86f1360befbd7c47d94  test.hex

$ tinygo build -o test.hex -target=cortex-m-qemu ./testdata/calls.go && md5sum test.hex
05b7cbd854f460a1bf3564b280ffea16  test.hex

I bisected this to 4e84531, which is the reflect refactor.

[aykevl]

Smaller reproducer:

package main

type Thing struct {
	name string
}

func (t Thing) Foo() {
}

type Printer interface {
	Foo()
}

func main() {
	var t Printer = &Thing{"foo"}
	defer t.Foo()
}

[aykevl]

This was introduced and fixed during the current release cycle, so closing.