Close gap for x86_64-v3 ABI in TCG - CPU support for fma, f16c, avx, avx2 features required
Description of problem:
There are 3 additional ABIs defined by a collaboration of vendors for the `x86_64` architecture, over the original baseline:

* https://gitlab.com/x86-psABIs/x86-64-ABI/-/blob/master/x86-64-ABI/low-level-sys-info.tex

This is no problem for KVM assuming suitable host hardware, but TCG is currently unable to support more than the original baseline and the `x86_64-v2` step.  

For `x86_64-v3` there are some gaps in its emulation coverage. This can be seen by taking `Nehalem` which is a good fit for `x86_64-v2`, and requesting the extra v3 features:

```
$ qemu-system-x86_64 -accel tcg -cpu Nehalem,+avx,+avx2,+bmi1,+bmi2,+f16c,+fma,+abm,+movbe
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.fma [bit 12]
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.avx [bit 28]
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.f16c [bit 29]
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.07H:EBX.avx2 [bit 5]
```

IOW, the strict bare minimum TCG needs in order to satisfy `x86_64-v3` is  `fma`, `f16c`, `avx` and `avx2` support

If we want to fully support a named CPU model satisfying v3, then `Haswell` is the closest and that has a few additional gaps

```
$ qemu-system-x86_64 -accel tcg -cpu Haswell-noTSX
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.fma [bit 12]
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.pcid [bit 17]
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.x2apic [bit 21]
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.tsc-deadline [bit 24]
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.avx [bit 28]
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.01H:ECX.f16c [bit 29]
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.07H:EBX.avx2 [bit 5]
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.07H:EBX.invpcid [bit 10]

```

Those additional gaps wouldn't impact ability to execute binaries build for the `x86_64-v3` ABI though, so not as important.

The reason `x86_64-v3` compatibility in TCG matters is because sooner or later some Linux OS are going to set this as the baseline for their compiler toolchain.  There is a proposal to set this in `Fedora ELN`, which is what feeds in to a possible future `RHEL-10`.

I imagine adding these extra features would be non-negligible work in TCG / take some time to complete.

Thus I file this bug for the purpose of suggesting these 4 specific missing features be considered a priority to address, compared to other missing CPU features in TCG that might be considered more of a 'nice to have'.

eg looking further the `x86_64-v4` baseline brings in a requirement for `avx512f`, `avx512bw`, `avx512cd`, `avx512dq`, `avx512vl` which TCG also lacks, but I don't think they really need to be considered important at this point in time.