[MSan] Fix minor issues in testcases (#144073)

Previously,
1. ifaddrs.cpp : mistake `size_t (xxx)` as `sizeof (xxx)`, resulting in 
inadequate checks.
2. qsort.cpp : mistake `kSize2` as `kSize1`, resulting in an unexpected
buffer overlow issue.

compiler-rt/test/msan/ifaddrs.cpp

@@ -18,7 +18,7 @@
 
 #define CHECK_AND_PUSH(addr, size)                                             \
   if (addr) {                                                                  \
-    assert(-1 == __msan_test_shadow(addr, sizeof(size)));         \
+    assert(-1 == __msan_test_shadow(addr, (size_t)(size)));                    \
     ranges.push_back(std::make_pair((void *)addr, (size_t)size));              \
   }
 
@@ -35,7 +35,7 @@ int main(int argc, char *argv[]) {
   assert(res == 0);
   assert(-1 == __msan_test_shadow(&ifas, sizeof(ifaddrs *)));
 
-  std::vector<std::pair<void *, size_t> > ranges;
+  std::vector<std::pair<void *, size_t>> ranges;
   ifaddrs *p = ifas;
   while (p) {
     CHECK_AND_PUSH(p, sizeof(ifaddrs));

compiler-rt/test/msan/qsort.cpp

@@ -52,7 +52,7 @@ int compar1(const void *a, const void *b) {
   // kind of random
   for (int i = 0; i < kSize2; ++i)
     p[i] = i * 2 + (i % 3 - 1) * 3;
-  qsort(p, kSize1, sizeof(long), compar2);
+  qsort(p, kSize2, sizeof(long), compar2);
   __msan_check_mem_is_initialized(p, sizeof(long) * kSize2);
   delete[] p;