Fix HelperMethodFrame::UpdateRegDisplay on x86 (#65589)

While running managed debugger tests with x86 runtime debug build, I was
hiting an assert in MachineState::pRetAddress() method in a couple of
tests.
It turns out there was a bug in the HelperMethodFrame::UpdateRegDisplay
introduced about 5 years ago that only happens in DAC. The m_MachState
can be uninitialized when we enter the method and we were calling
m_MachState.pRetAddr() before performing the initialization.

This change fixes it.

src/coreclr/vm/i386/cgenx86.cpp

@@ -289,8 +289,6 @@ void HelperMethodFrame::UpdateRegDisplay(const PREGDISPLAY pRD)
 
     LOG((LF_GCROOTS, LL_INFO100000, "STACKWALK    HelperMethodFrame::UpdateRegDisplay cached ip:%p, sp:%p\n", m_MachState.GetRetAddr(), m_MachState.esp()));
 
-    pRD->PCTAddr = dac_cast<TADDR>(m_MachState.pRetAddr());
-
 #ifdef FEATURE_EH_FUNCLETS
 
     pRD->IsCallerContextValid = FALSE;
@@ -306,6 +304,7 @@ void HelperMethodFrame::UpdateRegDisplay(const PREGDISPLAY pRD)
 
         InsureInit(false, pUnwoundState);
 
+        pRD->PCTAddr = dac_cast<TADDR>(pUnwoundState->pRetAddr());
         pRD->pCurrentContext->Eip = pRD->ControlPC = pUnwoundState->GetRetAddr();
         pRD->pCurrentContext->Esp = pRD->SP        = pUnwoundState->esp();
 
@@ -325,6 +324,7 @@ void HelperMethodFrame::UpdateRegDisplay(const PREGDISPLAY pRD)
     }
 #endif // DACCESS_COMPILE
 
+    pRD->PCTAddr = dac_cast<TADDR>(m_MachState.pRetAddr());
     pRD->pCurrentContext->Eip = pRD->ControlPC = m_MachState.GetRetAddr();
     pRD->pCurrentContext->Esp = pRD->SP = (DWORD) m_MachState.esp();
 
@@ -401,6 +401,7 @@ void HelperMethodFrame::UpdateRegDisplay(const PREGDISPLAY pRD)
     pRD->pEbx = (DWORD*) m_MachState.pEbx();
     pRD->pEbp = (DWORD*) m_MachState.pEbp();
 
+    pRD->PCTAddr = dac_cast<TADDR>(m_MachState.pRetAddr());
     pRD->ControlPC = m_MachState.GetRetAddr();
     pRD->SP  = (DWORD) m_MachState.esp();