Hexagon instructions are VLIW "bundles" of up to four instruction words
encoded as a single MCInst with operands for each sub-instruction.
Previously, the disassembler's getInstruction() returned the full
bundle, which made it difficult to work with llvm-objdump.
For example, since all instructions are bundles, and bundles do not
branch, branch targets could not be printed.
This patch modifies the Hexagon disassembler to return individual
sub-instructions instead of entire bundles, enabling correct printing of
branch targets and relocations. It also introduces
`MCDisassembler::getInstructionBundle` for cases where the full bundle
is still needed.
By default, llvm-objdump separates instructions with newlines. However,
this does not work well for Hexagon syntax:
{ inst1
inst2
inst3
inst4 <branch> } :endloop0
Instructions may be followed by a closing brace, a closing brace with
`:endloop`, or a newline. Branches must appear within the braces.
To address this, `PrettyPrinter::getInstructionSeparator()` is added and
overridden for Hexagon.
(cherry picked from commit ac7ceb3dabfac548caa993e7b77bbadc78af4464)
b5043a0940