Fix Mem2Reg check on end_borrows of store_borrow

Instead of checking if the end_borrow is ending the lifetime of the store_borrow of the asi under consideration,
this code was checking if the store_borrow source is the runningValue which is incorrect in cases where a store_borrow
src to another destination gets replaced during mem2reg. This PR fixes the issue.

lib/SILOptimizer/Transforms/SILMem2Reg.cpp

@@ -1826,6 +1826,9 @@ void MemoryToRegisters::removeSingleBlockAllocation(AllocStackInst *asi) {
       if (!sbi) {
         continue;
       }
+      if (sbi->getDest() != asi) {
+        continue;
+      }
       if (!runningVals.hasValue()) {
         continue;
       }