Ensure test file YAML blocks don't have a trailing space. (#2018)

test/annexB/built-ins/String/prototype/anchor/B.2.3.2.js

test/annexB/built-ins/String/prototype/big/B.2.3.3.js

test/annexB/built-ins/String/prototype/blink/B.2.3.4.js

test/annexB/built-ins/String/prototype/bold/B.2.3.5.js

test/annexB/built-ins/String/prototype/fixed/B.2.3.6.js

test/annexB/built-ins/String/prototype/fontcolor/B.2.3.7.js

test/annexB/built-ins/String/prototype/fontsize/B.2.3.8.js

test/annexB/built-ins/String/prototype/italics/B.2.3.9.js

test/annexB/built-ins/String/prototype/link/B.2.3.10.js

test/annexB/built-ins/String/prototype/small/B.2.3.11.js

test/annexB/built-ins/String/prototype/strike/B.2.3.12.js

test/annexB/built-ins/String/prototype/sub/B.2.3.13.js

test/annexB/built-ins/String/prototype/sup/B.2.3.14.js

test/built-ins/MapIteratorPrototype/next/iteration.js

test/built-ins/Object/defineProperty/15.2.3.6-4-289-1.js

test/built-ins/Set/prototype/keys/keys.js

.../built-ins/Set/prototype/values/returns-iterator-empty.js

test/built-ins/Set/prototype/values/returns-iterator.js

...uilt-ins/Set/prototype/values/values-iteration-mutable.js

test/built-ins/SetIteratorPrototype/next/iteration.js