Add feature flags for various tests

test/language/expressions/async-generator/throw-suspendedYield-try-catch.js

@@ -13,6 +13,7 @@ info: |
   "suspendedYield", and generator is resumed within a try-block with an
   associated catch block, resume execution within catch-block.
 flags: [async]
+features: [async-iteration]
 ---*/
 
 var error = new Error('boop');

test/language/expressions/async-generator/throw-suspendedYield-try-finally-return.js

@@ -13,6 +13,7 @@ info: |
   "suspendedYield", and generator is resumed within a try-block with an
   associated finally block, resume execution within finally.
 flags: [async]
+features: [async-iteration]
 ---*/
 
 class Err extends Error {};

test/language/expressions/async-generator/throw-suspendedYield-try-finally-throw.js

@@ -14,6 +14,7 @@ info: |
   "suspendedYield", and generator is resumed within a try-block with an
   associated finally block, resume execution within finally.
 flags: [async]
+features: [async-iteration]
 ---*/
 
 var error = new Error('boop');

test/language/expressions/async-generator/throw-suspendedYield-try-finally.js

@@ -13,6 +13,7 @@ info: |
   "suspendedYield", and generator is resumed within a try-block with an
   associated finally block, resume execution within finally.
 flags: [async]
+features: [async-iteration]
 ---*/
 
 var error = new Error('boop');

test/language/expressions/async-generator/throw-suspendedYield.js

@@ -12,6 +12,7 @@ info: |
   "suspendedYield", generator is resumed and immediately and
   closes the generator and returns completion.
 flags: [async]
+features: [async-iteration]
 ---*/
 
 var error = new Error('boop');