Remove dead partial stores of return registers when possible

Version and Platform (required):

• Binary Ninja Version: 4.2.6188-dev (ab61b8dc)
• OS: Windows 11
• OS Version: 23H2
• CPU Architecture: x86-64

Bug Description:
In function sub_180001160 of the attached binary, result is defined as a single variable, stored in rax, but before each return, the variable should be split and merged with the return value. Binary ninja correctly shows just return 0 and return 1, but the stores into RAX for the return values are still shown when they should be hidden.

Steps To Reproduce:
Open the attached binary and let analysis finish.

Expected Behavior:
the stores into result before each of the returns should be hidden.

Screenshots/Video Recording:
Initial with return value changed to bool and reanalyzed:

Split into new variables (which binja warns could be incorrect):

Each new variable set to bool, which finally removes the store:

Binary:

• NativeNamedPipe.zip

Source code of the function:

• https://github.com/Lachee/unity-named-pipes/blob/master/UnityNamedPipe.Native/connection_win.cpp#L17

Additional Information:

• The source code is also just one line instead of split with an if statement: return handle != NULL && isOpened && handle != INVALID_HANDLE_VALUE;
• The fully reversed function looks like this:
  

Reproduce the issue by opening the attached NativeNamedPipe.zip binary and inspecting function sub_180001160 after analysis finishes. Compare the decompilation with connection_win.cpp, especially the one-line boolean return; done means the dead stores into RAX are hidden while the return values remain correct.