* [Text Blocks] ECJ's scanner should use JDK APIs to scan text blocks
rather than using hand coded versions.
Fixes https://github.com/eclipse-jdt/eclipse.jdt.core/issues/4150
Fixes https://github.com/eclipse-jdt/eclipse.jdt.core/issues/4153
Fixes https://github.com/eclipse-jdt/eclipse.jdt.core/issues/4129
* Regression test for https://bugs.eclipse.org/bugs/show_bug.cgi?id=561978
* Regression test for https://bugs.eclipse.org/bugs/show_bug.cgi?id=570719
* Regression test for https://bugs.eclipse.org/bugs/show_bug.cgi?id=570472
* Incorrect line numbers when parsing text blocks
* Fixes https://github.com/eclipse-jdt/eclipse.jdt.core/issues/2462