[vm/test] Fix memory leak in ffi/regress_flutter97301_test

TEST=ci
Fixes #48283

Change-Id: I22d9ebac3240e9ca84fec833340d71b58d01119d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/231335
Auto-Submit: Alexander Markov <[email protected]>
Reviewed-by: Siva Annamalai <[email protected]>
Commit-Queue: Siva Annamalai <[email protected]>

Author: alexmarkov

tests/ffi/regress_flutter97301_test.dart

@@ -18,4 +18,6 @@ main() {
   for (var i = 0; i < 2; i++) {
     print(offsetsPtr.asTypedList(1));
   }
+
+  calloc.free(offsetsPtr);
 }

tests/ffi_2/regress_flutter97301_test.dart

@@ -20,4 +20,6 @@ main() {
   for (var i = 0; i < 2; i++) {
     print(offsetsPtr.asTypedList(1));
   }
+
+  calloc.free(offsetsPtr);
 }