fix completion replacement offset/length for invalid token in switch statement

pkg/analysis_server/test/services/completion/completion_target_test.dart

Index: pkg/analysis_server/test/services/completion/completion_target_test.dart
diff --git a/pkg/analysis_server/test/services/completion/completion_target_test.dart b/pkg/analysis_server/test/services/completion/completion_target_test.dart
index 57fb4e93985bc831e687e59de6d0c10c0d6493f1..072f97c32317419c968ae4df63c80f626658a2a0 100644
--- a/pkg/analysis_server/test/services/completion/completion_target_test.dart
+++ b/pkg/analysis_server/test/services/completion/completion_target_test.dart
@@ -498,6 +498,30 @@ class C2 {
     assertTarget('zoo', 'zoo(z) {}');
   }
 
+  test_SwitchStatement_c() {
+    // Token('c') SwitchStatement
+    addTestSource('main() { switch(x) {c^} }');
+    assertTarget('}', 'switch (x) {}');
+  }
+
+  test_SwitchStatement_c2() {
+    // Token('c') SwitchStatement
+    addTestSource('main() { switch(x) { c^ } }');
+    assertTarget('}', 'switch (x) {}');
+  }
+
+  test_SwitchStatement_empty() {
+    // SwitchStatement
+    addTestSource('main() { switch(x) {^} }');
+    assertTarget('}', 'switch (x) {}');
+  }
+
+  test_SwitchStatement_empty2() {
+    // SwitchStatement
+    addTestSource('main() { switch(x) { ^ } }');
+    assertTarget('}', 'switch (x) {}');
+  }
+
   test_TypeArgumentList() {
     // TypeName  TypeArgumentList  TypeName
     addTestSource('main() { C<^> c; }');