[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/tests/SyntaxErrorInTestHighlighting.fir.kt

@@ -0,0 +1,5 @@
+// dummy test of syntax error highlighting in tests
+
+fun get() {
+    1 + 2 <!SYNTAX!>2 3 4<!>
+}