git: openjdk/jdk15u-dev: 8273826: Correct Manifest file name and NPE checks

[Yuri Nesterenko]

Changeset: 4753c728
Author:    Yuri Nesterenko <yan at openjdk.org>
Date:      2021-11-09 08:59:00 +0000
URL:       https://git.openjdk.java.net/jdk15u-dev/commit/4753c72860bed60ef1d1688addaeb550b980279c

8273826: Correct Manifest file name and NPE checks

Backport-of: 03a8d342b86e720d3cba08d540182b4ab161fba3

! src/java.base/share/classes/java/util/jar/JarFile.java
! src/java.base/share/classes/java/util/jar/JarInputStream.java
! src/java.base/share/classes/java/util/jar/JarVerifier.java
! src/java.base/share/classes/sun/security/util/ManifestEntryVerifier.java
+ test/jdk/sun/security/tools/jarsigner/warnings/LowerCaseManifest.java