Revert "CTS: Temporarily remove SystemApi presubmit"

This reverts commit e600c47f4b0b0a7cb3703cbb41d30bc0dd2accb1.

Reason for revert: Test failure has been fixed - http://b/116632058

Bug: 123990286
Change-Id: I2b9dc5f7be9f717b3b90bab02d45a5b82b8f4870
diff --git a/tests/signature/TEST_MAPPING b/tests/signature/TEST_MAPPING
index 1420499..2e49d6c 100644
--- a/tests/signature/TEST_MAPPING
+++ b/tests/signature/TEST_MAPPING
@@ -46,6 +46,9 @@
       "name": "CtsSystemApiAnnotationTestCases"
     },
     {
+      "name": "CtsSystemApiSignatureTestCases"
+    },
+    {
       "name": "CtsHiddenApiBlacklistApi28TestCases"
     },
     {