Remove trailing spaces from YAML blocks

[shvaikalesh]

This makes 7 tests pass in JSC:

test/built-ins/Function/StrictFunction_restricted-properties.js:
  default: 'Test262Error: Expected a TypeError to be thrown but no exception was thrown at all'
test/built-ins/Function/prototype/restricted-property-arguments.js:
  default: "ReferenceError: Can't find variable: verifyNotEnumerable"
  strict mode: "ReferenceError: Can't find variable: verifyNotEnumerable"
test/built-ins/Function/prototype/restricted-property-caller.js:
  default: "ReferenceError: Can't find variable: verifyNotEnumerable"
  strict mode: "ReferenceError: Can't find variable: verifyNotEnumerable"

JSC issue: test262-runner misbehaves when test file YAML has a trailing space.
Ref #1997.
Follow-up of #2018.