[X86 isel] Remove lane requirement from lowerShuffleAsUNPCKAndPermute

`lowerShuffleAsUNPCKAndPermute` requires the shuffle mask element to be
in the same lane in both the input and output vectors. This prevents it from
matching certain patterns for example in [GHI
61964](https://github.com/llvm/llvm-project/issues/61964). Removing the lane
requirement fixes the issue.

The change I'm targeting is in the test llvm/test/CodeGen/X86/pr61964.ll. The
codegen has improved notably with this patch. Otherwise, looks like some
broadcast instructions are replaced with unpck and perm. To check if there's
any other performance change, I ran llvm-test-suite benchmarks from the
SingleSource, MultiSource, and MicroBenchmarks directories:
```
Tests: 2665
Short Running: 2009 (filtered out)
Same hash: 140 (filtered out)
In Blacklist: 513 (filtered out)
Remaining: 3
Metric: exec_time

Program                                                                exec_time
                                                                       lhs       rhs    diff
 test-suite :: MultiSource/Benchmarks/ASCI_Purple/SMG2000/smg2000.test   1.64      1.64  0.1%
      test-suite :: SingleSource/Benchmarks/Adobe-C++/loop_unroll.test   1.06      1.06  0.0%
          test-suite :: MultiSource/Applications/JM/lencod/lencod.test   5.25      5.25  0.0%
                                                    Geomean difference    nan       nan  0.0%
      exec_time
l/r         lhs       rhs      diff
count  3.000000  3.000000  3.000000
mean   2.648300  2.649100  0.000462
std    2.269035  2.268849  0.000415
min    1.055500  1.055900  0.000095
25%    1.349300  1.350250  0.000237
50%    1.643100  1.644600  0.000379
75%    3.444700  3.445700  0.000646
max    5.246300  5.246800  0.000913
```
The patch only hits three cases and the result is neutral. (The 513 blacklisted
benchmarks are the ones under MicroBenchmarks, which `--filter-hash` does
not work and I manually verified their code did not change).

Differential Revision: https://reviews.llvm.org/D147668