NDK: r11 -> r11b

Just bug fixes.  Nothing terribly exciting.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1825213007

Review URL: https://codereview.chromium.org/1825213007
diff --git a/platform_tools/android/bin/utils/setup_toolchain.sh b/platform_tools/android/bin/utils/setup_toolchain.sh
index 0879fc9..10b7229 100755
--- a/platform_tools/android/bin/utils/setup_toolchain.sh
+++ b/platform_tools/android/bin/utils/setup_toolchain.sh
@@ -35,7 +35,7 @@
   TOOLCHAINS=${SCRIPT_DIR}/../toolchains
 
   ANDROID_ARCH=${ANDROID_ARCH-arm}
-  NDK=r11
+  NDK=r11b
 
   if [[ $ANDROID_ARCH == *64* ]]; then
       API=21  # Android 5.0