move import combinator suggestions into a separate computer

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

Index: pkg/analysis_server/test/services/completion/completion_test_util.dart
diff --git a/pkg/analysis_server/test/services/completion/completion_test_util.dart b/pkg/analysis_server/test/services/completion/completion_test_util.dart
index 148b013867c104aa69b4de06b01aec3c8c72845b..941b3b7701674a05210e92e9deb3ce486c0c6646 100644
--- a/pkg/analysis_server/test/services/completion/completion_test_util.dart
+++ b/pkg/analysis_server/test/services/completion/completion_test_util.dart
@@ -1068,33 +1068,7 @@ class AbstractSelectorSuggestionTest extends AbstractCompletionTest {
       class X {}''');
     computeFast();
     return computeFull(true).then((_) {
-      assertSuggestImportedClass(
-          'A',
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertSuggestImportedClass(
-          'B',
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertSuggestImportedClass(
-          'PB',
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertSuggestImportedTopLevelVar(
-          'T1',
-          null,
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertSuggestImportedFunction(
-          'F1',
-          'PB',
-          false,
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertNotSuggested('C');
-      assertNotSuggested('D');
-      assertNotSuggested('X');
-      assertNotSuggested('Object');
+      assertNoSuggestions();
     });
   }
 
@@ -1121,43 +1095,7 @@ class AbstractSelectorSuggestionTest extends AbstractCompletionTest {
       class X {}''');
     computeFast();
     return computeFull(true).then((_) {
-      assertSuggestImportedClass(
-          'A',
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertSuggestImportedClass(
-          'B',
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertSuggestImportedClass(
-          'PB',
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertSuggestImportedTopLevelVar(
-          'T1',
-          null,
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertSuggestImportedFunction(
-          'F1',
-          'PB',
-          false,
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertSuggestImportedClass(
-          'Clz',
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertSuggestImportedFunctionTypeAlias(
-          'F2',
-          null,
-          false,
-          CompletionRelevance.DEFAULT,
-          CompletionSuggestionKind.IDENTIFIER);
-      assertNotSuggested('C');
-      assertNotSuggested('D');
-      assertNotSuggested('X');
-      assertNotSuggested('Object');
+      assertNoSuggestions();
     });
   }
 
@@ -1289,6 +1227,23 @@ class AbstractSelectorSuggestionTest extends AbstractCompletionTest {
     });
   }
 
+  test_FormalParameterList() {
+    // FormalParameterList MethodDeclaration
+    addTestSource('''
+      foo() { }
+      void bar() { }
+      class A {a(^) { }}''');
+    computeFast();
+    return computeFull(true).then((_) {
+      assertSuggestLocalFunction('foo', null);
+      assertSuggestLocalMethod('a', 'A', null);
+      assertSuggestLocalClass('A');
+      assertSuggestImportedClass('String');
+      assertSuggestImportedFunction('identical', 'bool');
+      assertNotSuggested('bar');
+    });
+  }
+
   test_ForStatement_body() {
     // Block  ForStatement
     addTestSource('main(args) {for (int i; i < 10; ++i) {^}}');
@@ -1601,23 +1556,6 @@ class AbstractSelectorSuggestionTest extends AbstractCompletionTest {
     });
   }
 
-  test_FormalParameterList() {
-    // FormalParameterList MethodDeclaration
-    addTestSource('''
-      foo() { }
-      void bar() { }
-      class A {a(^) { }}''');
-    computeFast();
-    return computeFull(true).then((_) {
-      assertSuggestLocalFunction('foo', null);
-      assertSuggestLocalMethod('a', 'A', null);
-      assertSuggestLocalClass('A');
-      assertSuggestImportedClass('String');
-      assertSuggestImportedFunction('identical', 'bool');
-      assertNotSuggested('bar');
-    });
-  }
-
   test_MethodInvocation_no_semicolon() {
     // MethodInvocation  ExpressionStatement  Block
     addTestSource('''