Fix inference heuristic hacks

[simonster]

These were broken by #11274 but no one noticed. Fixes #13350.

[simonster]

With this PR:

➜  ~ julia --depwarn=no perf_parens.jl 
Warmup @time
  0.000002 seconds (148 allocations: 10.151 KB)
Without parentheses:
  0.071398 seconds (15 allocations: 624 bytes)
With parentheses:
  0.073499 seconds (15 allocations: 624 bytes)

[tkelman]

failing an llvm assertion on osx and windows?

Assertion failed: (isVirtualRegister(Reg) && "Not a virtual register"), function virtReg2Index, file /private/tmp/llvm33-julia-IYf1/llvm-3.3.src/include/llvm/Target/TargetRegisterInfo.h, line 293.
signal (6): Abort trap: 6
__pthread_kill at /usr/lib/system/libsystem_kernel.dylib (unknown line)
    From worker 3:       * functional           Worker 3 terminated.
ERROR (unhandled task failure): EOFError: read end of file

[timholy]

Thanks for looking into this, @simonster!

[simonster]

The LLVM assertion failure breaks the tests with this PR but is possible to trigger without it. Filed #13366.

[KristofferC]

Maybe it is possible to add a test for this?

[simonster]

I think it would be non-trivial to test directly and the logic is pretty simple. But we should definitely have a perf test for #5011 or #13350. I'll try to add that to @IainNZ's collection.

[JeffBezanson]

Excellent! Thanks for figuring this out.

[tkelman]

So should I be cherry-picking this into #13357 if the assertion failure is a master-only issue?

[simonster]

@tkelman Yes, I think so.

[JeffBezanson]

Bump. I think we should rebase and merge this.