Rebased version of #12706 (#12933) (#12944)

* Fix Flaky SettingTests Tests



* add the comment to unit test



---------



(cherry picked from commit 839ee4c)

Signed-off-by: kkewwei <kkewwei@163.com>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: kkewwei <kkewwei@163.com>

server/src/test/java/org/opensearch/common/settings/SettingTests.java

@@ -201,7 +201,7 @@ public void testMemorySize() {
         assertEquals(new ByteSizeValue(12), value.get());
 
         assertTrue(settingUpdater.apply(Settings.builder().put("a.byte.size", "20%").build(), Settings.EMPTY));
-        assertEquals(new ByteSizeValue((int) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * 0.2)), value.get());
+        assertEquals(new ByteSizeValue((long) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * 0.2)), value.get());
     }
 
     public void testMemorySizeWithFallbackValue() {
@@ -219,10 +219,12 @@ public void testMemorySizeWithFallbackValue() {
         assertEquals(memorySizeValue.getBytes(), JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * 0.2, 1.0);
 
         assertTrue(settingUpdater.apply(Settings.builder().put("a.byte.size", "30%").build(), Settings.EMPTY));
-        assertEquals(new ByteSizeValue((int) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * 0.3)), value.get());
+        // If value=getHeapMax()*0.3 is bigger than 2gb, and is bigger than Integer.MAX_VALUE,
+        // then (long)((int) value) will lose precision.
+        assertEquals(new ByteSizeValue((long) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * 0.3)), value.get());
 
         assertTrue(settingUpdater.apply(Settings.builder().put("b.byte.size", "40%").build(), Settings.EMPTY));
-        assertEquals(new ByteSizeValue((int) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * 0.4)), value.get());
+        assertEquals(new ByteSizeValue((long) (JvmInfo.jvmInfo().getMem().getHeapMax().getBytes() * 0.4)), value.get());
     }
 
     public void testSimpleUpdate() {