[llvm] [win][x64] Allow push/pop for stack alloc when unwind v2 is required (PR #153621)

[Eli Friedman via llvm-commits]

================
@@ -201,11 +201,6 @@ bool X86WinEHUnwindV2::runOnMachineFunction(MachineFunction &MF) {
                 "The epilog is deallocating a stack "
                 "allocation, but the prolog did "
                 "not allocate one");
-          if (HasStackDealloc)
----------------
efriedma-quic wrote:

Say you have a push and a stackalloc in the prologue.  Then you have a stackdealloc, a pop, and another stackdealloc in the epilogue.  We want to rejectCurrentFunctionInternalError in that case.  (Not sure how likely that is, but could happen with a callee-pop calling convention.)

https://github.com/llvm/llvm-project/pull/153621