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/android/defs.go b/android/defs.go
index b28d2fa..03968c1 100644
--- a/android/defs.go
+++ b/android/defs.go
@@ -232,7 +232,7 @@
 
 // ContentFromFileRuleForTests returns the content that was passed to a WriteFileRule for use
 // in tests.
-func ContentFromFileRuleForTests(t *testing.T, params TestingBuildParams) string {
+func ContentFromFileRuleForTests(t *testing.T, ctx *TestContext, params TestingBuildParams) string {
 	t.Helper()
 	if g, w := params.Rule, writeFile; g != w {
 		t.Errorf("expected params.Rule to be %q, was %q", w, g)