[SPARK-27397][CORE] Take care of OpenJ9 JVM in Spark

## What changes were proposed in this pull request?

This PR supports `OpenJ9` in addition to `IBM JDK` and `OpenJDK` in Spark by handling `System.getProperty("java.vendor") = "Eclipse OpenJ9"`.

In `inferDefaultMemory()` and `getKrb5LoginModuleName()`, this PR uses non `IBM` way.

```
$ ~/jdk-11.0.2+9_openj9-0.12.1/bin/jshell
|  Welcome to JShell -- Version 11.0.2
|  For an introduction type: /help intro

jshell> System.out.println(System.getProperty("java.vendor"))
Eclipse OpenJ9

jshell> System.out.println(System.getProperty("java.vm.info"))
JRE 11 Linux amd64-64-Bit Compressed References 20190204_127 (JIT enabled, AOT enabled)
OpenJ9   - 90dd8cb40
OMR      - d2f4534b
JCL      - 289c70b6844 based on jdk-11.0.2+9

jshell> System.out.println(Class.forName("com.ibm.lang.management.OperatingSystemMXBean").getDeclaredMethod("getTotalPhysicalMemory"))
public abstract long com.ibm.lang.management.OperatingSystemMXBean.getTotalPhysicalMemory()

jshell> System.out.println(Class.forName("com.sun.management.OperatingSystemMXBean").getDeclaredMethod("getTotalPhysicalMemorySize"))
public abstract long com.sun.management.OperatingSystemMXBean.getTotalPhysicalMemorySize()

jshell> System.out.println(Class.forName("com.ibm.security.auth.module.Krb5LoginModule"))
|  Exception java.lang.ClassNotFoundException: com.ibm.security.auth.module.Krb5LoginModule
|        at Class.forNameImpl (Native Method)
|        at Class.forName (Class.java:339)
|        at (#1:1)

jshell> System.out.println(Class.forName("com.sun.security.auth.module.Krb5LoginModule"))
class com.sun.security.auth.module.Krb5LoginModule
```

## How was this patch tested?

Existing test suites
Manual testing with OpenJ9.

Closes #24308 from kiszk/SPARK-27397.

Authored-by: Kazuaki Ishizaki <ishizaki@jp.ibm.com>
Signed-off-by: Sean Owen <sean.owen@databricks.com>

core/src/main/scala/org/apache/spark/util/SizeEstimator.scala

@@ -131,8 +131,9 @@ object SizeEstimator extends Logging {
       return System.getProperty(TEST_USE_COMPRESSED_OOPS_KEY).toBoolean
     }
 
-    // java.vm.info provides compressed ref info for IBM JDKs
-    if (System.getProperty("java.vendor").contains("IBM")) {
+    // java.vm.info provides compressed ref info for IBM and OpenJ9 JDKs
+    val javaVendor = System.getProperty("java.vendor")
+    if (javaVendor.contains("IBM") || javaVendor.contains("OpenJ9")) {
       return System.getProperty("java.vm.info").contains("Compressed Ref")
     }
 

launcher/src/main/java/org/apache/spark/launcher/CommandBuilderUtils.java

@@ -31,11 +31,6 @@ class CommandBuilderUtils {
   static final String DEFAULT_PROPERTIES_FILE = "spark-defaults.conf";
   static final String ENV_SPARK_HOME = "SPARK_HOME";
 
-  /** The set of known JVM vendors. */
-  enum JavaVendor {
-    Oracle, IBM, OpenJDK, Unknown
-  }
-
   /** Returns whether the given string is null or empty. */
   static boolean isEmpty(String s) {
     return s == null || s.isEmpty();
@@ -112,21 +107,6 @@ static boolean isWindows() {
     return os.startsWith("Windows");
   }
 
-  /** Returns an enum value indicating whose JVM is being used. */
-  static JavaVendor getJavaVendor() {
-    String vendorString = System.getProperty("java.vendor");
-    if (vendorString.contains("Oracle")) {
-      return JavaVendor.Oracle;
-    }
-    if (vendorString.contains("IBM")) {
-      return JavaVendor.IBM;
-    }
-    if (vendorString.contains("OpenJDK")) {
-      return JavaVendor.OpenJDK;
-    }
-    return JavaVendor.Unknown;
-  }
-
   /**
    * Updates the user environment, appending the given pathList to the existing value of the given
    * environment variable (or setting it if it hasn't yet been set).