[clang] [llvm] [X86][APX] Add copy instruction to LiveInterval of SrcReg (PR #191102)

[Dan Liew via cfe-commits]

delcypher wrote:

@phoebewang The test landed in this test is failing when expensive checks are enabled.

https://ci.swift.org/job/llvm.org/job/clang-stage1-RA-expensive/job/main/409/testReport/junit/Clang/CodeGen_X86/pr190962_ll/

```
# | *** Bad machine code: Two-address instruction operands must be identical ***
# | - function:    foo
# | - basic block: %bb.0  (0x7fc688853c40) [0B;192B)
# | - instruction: 128B	%10:gr64 = IMUL64rm %33:gr64(tied-def 0), %fixed-stack.1, 1, $noreg, 0, $noreg, implicit-def dead $eflags :: (load (s64) from %fixed-stack.1, align 16)
# | - operand 1:   %33:gr64(tied-def 0)
# | fatal error: error in backend: Found 1 machine code errors.
```

https://github.com/llvm/llvm-project/pull/191102