[llvm] [llvm][macho] Support the LC_TARGET_TRIPLE load command (PR #210276)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-m68k-linux-cross` running on `suse-gary-m68k-cross` while building `llvm` at step 5 "ninja check 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/27/builds/2557

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (ninja check 1) failure: stage 1 checked (failure)
******************** TEST 'LLVM :: MC/MachO/target-triple-padding.s' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
split-file /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/test/MC/MachO/target-triple-padding.s /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/test/MC/MachO/Output/target-triple-padding.s.tmp
# executed command: split-file /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/test/MC/MachO/target-triple-padding.s /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/test/MC/MachO/Output/target-triple-padding.s.tmp
# RUN: at line 3
/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-mc -triple arm64-ios-macabi /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/test/MC/MachO/Output/target-triple-padding.s.tmp/target-triple-always-has-nul.s -filetype=obj -o -  | /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-objdump --macho --private-headers - | /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/FileCheck /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/test/MC/MachO/Output/target-triple-padding.s.tmp/target-triple-always-has-nul.s
# executed command: /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-mc -triple arm64-ios-macabi /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/test/MC/MachO/Output/target-triple-padding.s.tmp/target-triple-always-has-nul.s -filetype=obj -o -
# .---command stderr------------
# | /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-mc: error: unable to get target for 'arm64-unknown-ios-macabi', see --version and --triple.
# `-----------------------------
# error: command failed with exit status: 1
# executed command: /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-objdump --macho --private-headers -
# executed command: /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/FileCheck /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/test/MC/MachO/Output/target-triple-padding.s.tmp/target-triple-always-has-nul.s
# .---command stderr------------
# | /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/test/MC/MachO/Output/target-triple-padding.s.tmp/target-triple-always-has-nul.s:7:11: error: CHECK: expected string not found in input
# | // CHECK: cmd LC_TARGET_TRIPLE
# |           ^
# | <stdin>:1:1: note: scanning from here
# | -: is not an object file
# | ^
# | <stdin>:1:18: note: possible intended match here
# | -: is not an object file
# |                  ^
# | 
# | Input file: <stdin>
# | Check file: /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/test/MC/MachO/Output/target-triple-padding.s.tmp/target-triple-always-has-nul.s
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |            1: -: is not an object file 
# | check:7'0    {                         } search range (exclusive bounds)
# | check:7'1                                error: no match found in search range
# | check:7'2                      ?         possible intended match
# | >>>>>>
# `-----------------------------
# error: command failed with exit status: 1

--

********************


```

</details>

https://github.com/llvm/llvm-project/pull/210276