Add NetHttpCoverageTests to mainline presubmit

Mainline presubmit runs on older images. So we need to set:
- min_sdk_version to the minimum sdk we support otherwise
it would default to current
- enforce_default_target_sdk_version since mainline needs
all modules to target the latest sdk

Test: presubmit
Bug: 263294440
Change-Id: I20757b13ab9ab45908dae088c6cb6b0bbc51989d
diff --git a/Cronet/tests/cts/Android.bp b/Cronet/tests/cts/Android.bp
index 945b220..41bfbc9 100644
--- a/Cronet/tests/cts/Android.bp
+++ b/Cronet/tests/cts/Android.bp
@@ -44,6 +44,7 @@
 android_library {
     name: "CtsNetHttpTestsLib",
     sdk_version: "test_current",
+    min_sdk_version: "30",
     srcs: [
         "src/**/*.java",
         "src/**/*.kt",
@@ -62,6 +63,7 @@
         "framework-tethering",
         "org.apache.http.legacy",
     ],
+    lint: { test: true }
 }
 
 android_test {