Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

nofirst-symbol-disassembly.test
// RUN: llvm-objdump -d --macho %p/Inputs/nofirst-symbol.macho-x86_64 | FileCheck %s

CHECK:        0:	90 	nop
CHECK: _foo:
CHECK:        1:	c3 	retq
CHECK: _bar:
CHECK:        2:	90 	nop
CHECK:        3:	c3 	retq