[llvm] Delete the incorrect assert that assumes size of `APFloat` is the same as `IEEEFloat`. (PR #111780)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

Can you please try to compile the following code with your compiler? https://godbolt.org/z/4jqhnjG3E
```
struct Empty {};
struct FloatImpl1 { float x; };
struct FloatImpl2 { float x; };
struct Float : public Empty {
    union {FloatImpl1 impl1;FloatImpl2 impl2;};
};

static_assert(sizeof(Float) == sizeof(float));
```


https://github.com/llvm/llvm-project/pull/111780