Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

eh_frame_zero_cie.test
# RUN: llvm-objdump --dwarf=frames %p/Inputs/eh_frame_zero_cie.o 2>/dev/null | FileCheck %s

# CHECK:       .eh_frame contents:
# CHECK-EMPTY:
# CHECK-NEXT:  00000000 ZERO terminator
# CHECK-NOT:   {{.}}