Fix test cases.

Author: branh

docs/sanitizers/error-global-buffer-overflow.md

@@ -126,8 +126,10 @@ int main(int argc, char **argv) {
     case 'g': return global[one * 11];     //Boom! simple global
     case 'c': return C::array[one * 11];   //Boom! class static
     case 'f':
+    {
         static int array[10] = {};
         return array[one * 11];            //Boom! function static
+    }
     case 'l':
         // literal global ptr created by compiler
         const char *str = "0123456789";

docs/sanitizers/error-stack-buffer-overflow.md

@@ -86,7 +86,7 @@ public:
 
 class Child : public Parent {
 public:
-    int extra_field;
+    volatile int extra_field;
 };
 
 int main(void) {

docs/sanitizers/error-stack-use-after-return.md

@@ -21,7 +21,7 @@ This check can slow your application down substantially. Consider the [Clang sum
 ```cpp
 // example1.cpp
 // stack-use-after-return error
-char* x;
+volatile char* x;
 
 void foo() {
     char stack_buffer[42];

docs/sanitizers/error-stack-use-after-scope.md

@@ -147,10 +147,12 @@ void main() {
 To build and test this example, run these commands in a Visual Studio 2019 version 16.9 or later [developer command prompt](../build/building-on-the-command-line.md#developer_command_prompt_shortcuts):
 
 ```cmd
-cl example4.cpp /EHsc /fsanitize=address /Zi
+cl example4.cpp /EHsc /fsanitize=address /Zi /Od
 devenv /debugexe example4.exe
 ```
 
+ASAN is a form of dynamic analysis, which means it can only detect bad code that is actually executed. An optimizer may propagate the value of `v` in these cases instead of reading from the address stored in `p`. As a result, this example requires the `/Od` flag.
+
 ### Resulting error - temporaries
 
 :::image type="content" source="media/stack-use-after-scope-example-4.png" alt-text="Screenshot of debugger displaying stack-use-after-scope error in example 4.":::