[ELF] - Make LLD accept Ttext-segment X/Ttext-segment=X aliases for -Ttext.

It os used in work/emulators/qemu-user-static port.
Which tries to use -Ttext-segment and then:

# In case ld does not support -Ttext-segment, edit the default linker
# script via sed to set the .text start addr.  This is needed on FreeBSD
# at least.
<here it calls -verbose to extract and edit default bfd linker script.>

Actually now we are do not fully support -Ttext properly (see D27613),
but we also seems never will provide anything close to default script, like bfd do,
so at least this patch introduces proper alias handling.

llvm-svn: 289827