LibGLSL: Add tests for GLSL parser

Userland/Libraries/LibGLSL/Tests/parser/if-else.ast

@@ -0,0 +1,26 @@
+TranslationUnit[0:0->6:0]
+  FunctionDeclaration[0:0->6:0]
+    Type[0:0->0:3]
+      bool
+    foo
+    (
+    )
+    FunctionDefinition[1:0->6:0]
+    {
+      IfStatement[2:4->5:20]
+        Predicate:
+        BinaryExpression[2:8->2:14]
+          NumericLiteral[2:8->2:8]
+            1
+          ==
+          NumericLiteral[2:13->2:13]
+            2
+        Then:
+        ReturnStatement[3:8->3:19]
+          BooleanLiteral[3:15->3:18]
+            true
+        Else:
+        ReturnStatement[5:8->5:20]
+          BooleanLiteral[5:15->5:19]
+            false
+    }