Bug 85403 [quick assist] convert 'switch' into if-else-if fails if case has block
I20050215-2300 test case: switch (a) { case 1 : { System.out.println("1"); break; } }
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/correction/AdvancedQuickAssistProcessor.java
String label= CorrectionMessages.AdvancedQuickAssistProcessor_pickSelectedString;
		Image image= JavaPluginImages.get(JavaPluginImages.IMG_CORRECTION_LOCAL);
		LinkedCorrectionProposal proposal= new LinkedCorrectionProposal(label, context.getCompilationUnit(), rewrite, 1, image);
		proposal.addLinkedPosition(rewrite.track(centerLiteral), true, "CENTER_STRING"); 
		resultingCollections.add(proposal);
		return true;
	}
	private static Statement getSingleStatement(Statement statement) {
		if (statement instanceof Block) {
			List blockStatements= ((Block) statement).statements();
			if (blockStatements.size() != 1) {
				return null;
			}
			return (Statement) blockStatements.get(0);
		}
		return statement;
	}
	private static boolean getReplaceIfElseWithConditionalProposals(IInvocationContext context, ASTNode node, Collection resultingCollections) {
		if (!(node instanceof IfStatement)) {
			return false;
		}
		IfStatement ifStatement= (IfStatement) node;
		Statement thenStatement= getSingleStatement(ifStatement.getThenStatement());
		Statement elseStatement= getSingleStatement(ifStatement.getElseStatement());
		if (thenStatement == null || elseStatement == null) {
			return false;
		}
		Expression assigned= null;
		Expression thenExpression= null;