Add TestContext parameter to ContentFromFileRuleForTests

The next CL will need a TestContext parameter in
ContentFromFileRuleForTests in order to retrieve the file rule contents
from the Config.  Add it and update all the tests that use it in order
to simply review of the next CL.

Bug: 306029038
Test: go test ./...
Change-Id: Ia4b4c9854017ea3472fa2f8ba42cf7f72720496e
diff --git a/cc/testing.go b/cc/testing.go
index 71d986b..b1583f1 100644
--- a/cc/testing.go
+++ b/cc/testing.go
@@ -797,7 +797,7 @@
 func checkOverrides(t *testing.T, ctx *android.TestContext, singleton android.TestingSingleton, jsonPath string, expected []string) {
 	t.Helper()
 	out := singleton.MaybeOutput(jsonPath)
-	content := android.ContentFromFileRuleForTests(t, out)
+	content := android.ContentFromFileRuleForTests(t, ctx, out)
 
 	var flags snapshotJsonFlags
 	if err := json.Unmarshal([]byte(content), &flags); err != nil {