Recognize Checker Framework declaration annotations.

We are migrating Guava to use these annotations rather than jsr305's
@Nullable. We can't use the Checker Framework's _@Nullable_ yet because
we promise compatibility with Java 7, which doesn't support type
annotations. This is related to but distinct from
https://youtrack.jetbrains.com/issue/KT-21408, which is about a
different jsr305 annotation we use, @ParametersAreNonnullByDefault.

I've also updated some docs to mention Kotlin's existing support for the
Checker Framework _@NonNull_.

core/descriptors.jvm/src/org/jetbrains/kotlin/load/java/JvmAnnotationNames.kt

@@ -24,6 +24,7 @@ val NULLABLE_ANNOTATIONS = listOf(
         FqName("com.android.annotations.Nullable"),
         FqName("org.eclipse.jdt.annotation.Nullable"),
         FqName("org.checkerframework.checker.nullness.qual.Nullable"),
+        FqName("org.checkerframework.checker.nullness.compatqual.NullableDecl"),
         FqName("javax.annotation.Nullable"),
         FqName("javax.annotation.CheckForNull"),
         FqName("edu.umd.cs.findbugs.annotations.CheckForNull"),
@@ -42,6 +43,7 @@ val NOT_NULL_ANNOTATIONS = listOf(
         FqName("com.android.annotations.NonNull"),
         FqName("org.eclipse.jdt.annotation.NonNull"),
         FqName("org.checkerframework.checker.nullness.qual.NonNull"),
+        FqName("org.checkerframework.checker.nullness.compatqual.NonNullDecl"),
         FqName("lombok.NonNull"),
         FqName("io.reactivex.annotations.NonNull")
 )