[Analysis API] Collect designations only for autonomous declarations

Parameters, type parameters, and property accessors are not
self-sufficient declarations (their resolution depends on resolution
of their parent), so a proper designation path cannot be computed
for them.

Without a designation path, 'ContextCollector' performs analysis of the
whole file, which is inefficient.

analysis/low-level-api-fir/testData/contextCollector/primaryConstructor.kt

@@ -0,0 +1,4 @@
+class Foo<expr>(
+    val a: String = "foo"
+    val b: Int = a.length
+)</expr>