8208699: remove unneeded imports from runtime tests

Backport-of: 940ac1c

Author: Amos Shi

test/hotspot/jtreg/runtime/SharedArchiveFile/CdsSameObjectAlignment.java

@@ -36,7 +36,6 @@
 import jdk.test.lib.Platform;
 import jdk.test.lib.cds.CDSTestUtils;
 import jdk.test.lib.process.OutputAnalyzer;
-import jtreg.SkippedException;
 
 public class CdsSameObjectAlignment {
     public static void main(String[] args) throws Exception {

test/hotspot/jtreg/runtime/XCheckJniJsig/XCheckJSig.java

@@ -37,7 +37,6 @@
 import jdk.test.lib.process.ProcessTools;
 import jdk.test.lib.process.OutputAnalyzer;
 import jdk.test.lib.Platform;
-import jtreg.SkippedException;
 
 public class XCheckJSig {
     public static void main(String args[]) throws Throwable {