test: use standard logging methods from testing for the test helpers

Use the logging methods from testing.TB to make use of tb.Helper(). This
allows the tests to log the filename and line number in which the test
helper was called. Previously the test helper was logged which is rarely
useful.

cmd/restic/integration_test.go

@@ -31,6 +31,7 @@ import (
 )
 
 func parseIDsFromReader(t testing.TB, rd io.Reader) restic.IDs {
+	t.Helper()
 	IDs := restic.IDs{}
 	sc := bufio.NewScanner(rd)
 
@@ -148,6 +149,7 @@ func testRunRestoreAssumeFailure(snapshotID string, opts RestoreOptions, gopts G
 }
 
 func testRunCheck(t testing.TB, gopts GlobalOptions) {
+	t.Helper()
 	opts := CheckOptions{
 		ReadData:    true,
 		CheckUnused: true,