system-clang-format: Add Standard: Cpp11

clang-format tries to automatically detect the Cpp standard used,
particularly when determining to put spaces in template definitions:

Cpp03: std::vector<std::pair<bool, bool> >
vs
Cpp11: std::vector<std::pair<bool, bool>>

It doesn't always get this correct as seen in
https://android-review.googlesource.com/c/platform/system/core/+/973463/8
but since we know that all code within Android is C++17, we can safely
assume it should be formatted with the newer standard.

Test: clang-format doesn't break the above change.
Change-Id: I7d1d709690b7bca6da3863cc9a58e53eaec751b0

scripts/system-clang-format

@@ -1,4 +1,5 @@
 BasedOnStyle: Google
+Standard: Cpp11
 AccessModifierOffset: -2
 AllowShortFunctionsOnASingleLine: Inline
 ColumnLimit: 100

scripts/system-clang-format-2

@@ -1,4 +1,5 @@
 BasedOnStyle: Google
+Standard: Cpp11
 AllowShortFunctionsOnASingleLine: Inline
 ColumnLimit: 100
 CommentPragmas: NOLINT:.*