Ensure thumb bit is set when searching for debugger jit info on ARM (#…

…17617)

* Ensure thumb bit is set when searching for debugger jit info on ARM

* Make GetCodeStartAddress return correct PCODE, rather than fixing it at the callee site

* Fix type in daccess.h

* Use PINSTRToPCODE rather than manually adding the thumb bit

src/inc/daccess.h

@@ -2414,7 +2414,7 @@ typedef DPTR(RUNTIME_FUNCTION) PTR_RUNTIME_FUNCTION;
 //----------------------------------------------------------------------------
 //
 // A PCODE is a valid PC/IP value -- a pointer to an instruction, possibly including some processor mode bits.
-// (On ARM, for example, a PCODE value should should have the low-order THUMB_CODE bit set if the code should
+// (On ARM, for example, a PCODE value should have the low-order THUMB_CODE bit set if the code should
 // be executed in that mode.)
 //
 typedef TADDR PCODE;

src/vm/codeman.cpp

@@ -4166,7 +4166,7 @@ PCODE ExecutionManager::GetCodeStartAddress(PCODE currentPC)
     EECodeInfo codeInfo(currentPC);
     if (!codeInfo.IsValid())
         return NULL;
-    return (PCODE)codeInfo.GetStartAddress();
+    return PINSTRToPCODE(codeInfo.GetStartAddress());
 }
 
 //**************************************************************************