Update cppcheck (#5108)

Re-enable cppcheck CI job

Update cppcheck suppression list:
    The new version of cppcheck raises warnings for many potential
    issues that are guarded against, so those warnings have been
    supressed.

Handle realloc failures:
    - jerry-ext/util/sources.c
    - jerry-port/common/jerry-port-io.c

Refactor test-snapshot: move each test to separate functions like some
others already were.

Rename `handler` variables inside `main` of `test-api.c` as they
shadowed the `handler` function in the same file.

JerryScript-DCO-1.0-Signed-off-by: Máté Tokodi mate.tokodi@szteszoftver.hu

jerry-ext/handle-scope/handle-scope.c

@@ -254,10 +254,7 @@ jerryx_escape_handle_internal (jerryx_escapable_handle_scope scope,
      * Escape handle to parent scope
      */
     *result = jerryx_handle_scope_add_handle_to (found_handle, parent);
-  }
 
-  if (should_promote)
-  {
     scope->escaped = true;
   }
   return jerryx_handle_scope_ok;

jerry-ext/util/sources.c

@@ -146,6 +146,10 @@ jerryx_source_exec_stdin (void)
 
     jerry_size_t new_size = source_size + line_size;
     source_p = realloc (source_p, new_size);
+    if (source_p == NULL)
+    {
+      return jerry_throw_sz (JERRY_ERROR_COMMON, "Out of memory.");
+    }
 
     memcpy (source_p + source_size, line_p, line_size);
     jerry_port_line_free (line_p);