Merge pull request ARMmbed#13171 from LDong-Arm/reenable_aws_example

Re-enable AWS example, limit targets

Author: 0xc0170

tools/test/examples/examples.json

@@ -477,10 +477,10 @@
       "sub-repo-example": false,
       "subs": [],
       "features" : [],
-      "targets" : [],
+      "targets" : ["DISCO_L475VG_IOT01A", "K64F"],
       "toolchains" : [],
       "exporters": [],
-      "compile" : false,
+      "compile" : true,
       "export": true,
       "test" : false,
       "baud_rate": 115200,