Change GoogleTest flag removal to not read beyond the end of the array

to the NULL terminator.  #4532 says ASAN complains about this on some
platforms, although it is not clear if ASAN or the platform implementation
is incorrect about accessing the terminating NULL.

Fixes #4532

PiperOrigin-RevId: 635886009
Change-Id: Ibb4237055488c895b1dd09145ab979347bb9a390

googletest/src/gtest.cc

@@ -6700,17 +6700,17 @@ void ParseGoogleTestFlagsOnlyImpl(int* argc, CharType** argv) {
     }
 
     if (remove_flag) {
-      // Shift the remainder of the argv list left by one.  Note
-      // that argv has (*argc + 1) elements, the last one always being
-      // NULL.  The following loop moves the trailing NULL element as
-      // well.
-      for (int j = i; j != *argc; j++) {
-        argv[j] = argv[j + 1];
+      // Shift the remainder of the argv list left by one.
+      for (int j = i + 1; j < *argc; ++j) {
+        argv[j - 1] = argv[j];
       }
 
       // Decrements the argument count.
       (*argc)--;
 
+      // Terminate the array with nullptr.
+      argv[*argc] = nullptr;
+
       // We also need to decrement the iterator as we just removed
       // an element.
       i--;