Fix out-of-bounds access in JSONStream test.

Found using AddressSanitizer.

R=asiva@google.com

Review URL: https://codereview.chromium.org//821193003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@42562 260f80e4-7a28-3924-810f-c04153c831b5
Fix leak from new/free mismatch in main.

Found using AddressSanitizer.

R=asiva@google.com

Review URL: https://codereview.chromium.org//819363002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@42563 260f80e4-7a28-3924-810f-c04153c831b5