Fix DebugInfo async local var number

src/coreclr/jit/lclvars.cpp

@@ -1126,26 +1126,29 @@ unsigned Compiler::compMap2ILvarNum(unsigned varNum) const
         return (unsigned)ICorDebugInfo::UNKNOWN_ILNUM;
     }
 
+    unsigned originalVarNum = varNum;
+
     // Now mutate varNum to remove extra parameters from the count.
-    if (((info.compMethodInfo->args.callConv & CORINFO_CALLCONV_PARAMTYPE) != 0) && (varNum > info.compTypeCtxtArg))
+    if (((info.compMethodInfo->args.callConv & CORINFO_CALLCONV_PARAMTYPE) != 0) &&
+        (originalVarNum > info.compTypeCtxtArg))
     {
         varNum--;
     }
 
-    if (info.compIsVarArgs && (varNum > lvaVarargsHandleArg))
+    if (info.compIsVarArgs && (originalVarNum > lvaVarargsHandleArg))
     {
         varNum--;
     }
 
-    if ((lvaAsyncContinuationArg != BAD_VAR_NUM) && (varNum > lvaAsyncContinuationArg))
+    if ((lvaAsyncContinuationArg != BAD_VAR_NUM) && (originalVarNum > lvaAsyncContinuationArg))
     {
         varNum--;
     }
 
     // Is there a hidden argument for the return buffer. Note that this code
     // works because if the RetBuffArg is not present, compRetBuffArg will be
     // BAD_VAR_NUM
-    if ((info.compRetBuffArg != BAD_VAR_NUM) && (varNum > info.compRetBuffArg))
+    if ((info.compRetBuffArg != BAD_VAR_NUM) && (originalVarNum > info.compRetBuffArg))
     {
         varNum--;
     }