[Integrated] RFR: 8238951: Update jextract after JDK-8238226

[Jorn Vernee]

Changeset: b04a7574
Author:    Jorn Vernee <jvernee at openjdk.org>
Date:      2020-02-12 12:31:24 +0000
URL:       https://git.openjdk.java.net/panama-foreign/commit/b04a7574

8238951: Update jextract after JDK-8238226

Reviewed-by: mcimadamore

! src/jdk.incubator.jextract/share/classes/jdk/incubator/jextract/tool/JavaSourceBuilder.java
! src/jdk.incubator.jextract/share/classes/jdk/incubator/jextract/tool/resources/RuntimeHelper.template
! src/jdk.incubator.jextract/share/classes/jdk/internal/clang/Utils.java
! src/jdk.incubator.jextract/share/classes/jdk/internal/clang/libclang/Index_h.java
! src/jdk.incubator.jextract/share/classes/jdk/internal/jextract/impl/LayoutUtils.java
! test/jdk/tools/jextract/testStruct/struct.h