Sealed and non-sealed modifiers and permitted types not accessible through ITypeBinding

[subyssurendran666]

Added the unit tests and added the modifiers to the resolve bindings for sealed and non-sealed modifiers

What it does

The 'sealed' and 'non-sealed' modifiers are visible and accessible through the AST, but not when trying to get the same information with the associated type binding. Therefore added the modifiers in the TypeBiding for the sealed and non-sealed modifiers.

How to test

This PR closes #3178

Author checklist

• I have thoroughly tested my changes
• The change is following the coding conventions
• I have signed the Eclipse Contributor Agreement (ECA)

[jarthana]

@subyssurendran666 The patch looks good, however, I just noticed that we need to handle interface + sealed as well. For e.g, consider the below code:

		    		sealed interface A permits X {}
	    			public final  class X implements A {}

Querying isSealed() on A is going to return false. I think in the getModifiers(), we should do similar fix in isInterface() branch also.
Also, it is better if we just used assertTrue and assertFalse instead of assertEquals in the tests, isn't it?

[subyssurendran666]

@subyssurendran666 The patch looks good, however, I just noticed that we need to handle interface + sealed as well. For e.g, consider the below code:

		    		sealed interface A permits X {}
	    			public final  class X implements A {}

Querying isSealed() on A is going to return false. I think in the getModifiers(), we should do similar fix in isInterface() branch also. Also, it is better if we just used assertTrue and assertFalse instead of assertEquals in the tests, isn't it?

I have a incorporated the changes. Thanks for the suggestions.