Revert "fix backoff time"

[marsishandsome]

Reverts #241 because test fails

https://ci.pingcap.net/blue/organizations/jenkins/tikv-client-java_ghpr_integration_test/detail/tikv-client-java_ghpr_integration_test/130/pipeline/

[2021-08-05T02:42:58.333Z] testRetryPolicy(org.tikv.common.PDClientTest)  Time elapsed: 0.638 sec  <<< FAILURE!

[2021-08-05T02:42:58.333Z] java.lang.AssertionError

[2021-08-05T02:42:58.333Z] 	at org.junit.Assert.fail(Assert.java:86)

[2021-08-05T02:42:58.333Z] 	at org.junit.Assert.fail(Assert.java:95)

[2021-08-05T02:42:58.333Z] 	at org.tikv.common.PDClientTest.testRetryPolicy(PDClientTest.java:203)

[2021-08-05T02:42:58.333Z] 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

[2021-08-05T02:42:58.333Z] 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

[2021-08-05T02:42:58.333Z] 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

[2021-08-05T02:42:58.333Z] 	at java.lang.reflect.Method.invoke(Method.java:498)

[2021-08-05T02:42:58.333Z] 	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)

[2021-08-05T02:42:58.333Z] 	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)

[2021-08-05T02:42:58.333Z] 	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)

[2021-08-05T02:42:58.333Z] 	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)

[2021-08-05T02:42:58.333Z] 	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)

[2021-08-05T02:42:58.333Z] 	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)

[2021-08-05T02:42:58.333Z] 	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)

[2021-08-05T02:42:58.333Z] 	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)

[2021-08-05T02:42:58.333Z] 	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)

[2021-08-05T02:42:58.333Z] 	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)

[2021-08-05T02:42:58.333Z] 	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)

[2021-08-05T02:42:58.333Z] 	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)

[2021-08-05T02:42:58.333Z] 	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)

[2021-08-05T02:42:58.333Z] 	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)

[2021-08-05T02:42:58.333Z] 	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)

[2021-08-05T02:42:58.333Z] 	at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252)

[2021-08-05T02:42:58.333Z] 	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141)

[2021-08-05T02:42:58.333Z] 	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112)

[2021-08-05T02:42:58.334Z] 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

[2021-08-05T02:42:58.334Z] 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

[2021-08-05T02:42:58.334Z] 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

[2021-08-05T02:42:58.334Z] 	at java.lang.reflect.Method.invoke(Method.java:498)

[2021-08-05T02:42:58.334Z] 	at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)

[2021-08-05T02:42:58.334Z] 	at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)

[2021-08-05T02:42:58.334Z] 	at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)

[2021-08-05T02:42:58.334Z] 	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115)

[2021-08-05T02:42:58.334Z] 	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75)

[marsishandsome]

/run-all-tests