[test] Add test case for raw identifier semantic tokens

rdar://152273926

Author: hamishknight

test/SourceKit/SemanticTokens/raw_identifiers.swift

@@ -0,0 +1,33 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %sourcekitd-test -req=semantic-tokens %t/main.swift -- %t/main.swift > %t/result.json
+// RUN: diff -u %t/tokens.json %t/result.json
+
+//--- main.swift
+func `foo`(x: Int) {}
+`foo`(x: 0)
+
+func `foo bar baz`() {}
+`foo bar baz`()
+
+//--- tokens.json
+{
+  key.semantic_tokens: [
+    {
+      key.kind: source.lang.swift.ref.struct,
+      key.offset: 14,
+      key.length: 3,
+      key.is_system: 1
+    },
+    {
+      key.kind: source.lang.swift.ref.function.free,
+      key.offset: 22,
+      key.length: 5
+    },
+    {
+      key.kind: source.lang.swift.ref.function.free,
+      key.offset: 59,
+      key.length: 13
+    }
+  ]
+}