Bug 577522 - Use Import-Package for assertj

This will allow to more easily move to upstream dependency.

Change-Id: Ibcff9762873a8081e540f4b0253ce6b5ad488af3

Author: mickaelistria

ui/org.eclipse.pde.junit.runtime.tests/META-INF/MANIFEST.MF

@@ -17,5 +17,5 @@ Require-Bundle: org.junit,
  org.eclipse.jdt.core;bundle-version="3.19.0",
  org.eclipse.debug.ui;bundle-version="3.14.200",
  org.eclipse.ui;bundle-version="3.114.0",
- org.assertj;bundle-version="3.14.0",
  org.eclipse.pde.ui.tests;bundle-version="3.11.500"
+Import-Package: org.assertj.core.api;version="3.14.0"

ui/org.eclipse.pde.ui.tests/META-INF/MANIFEST.MF

@@ -40,8 +40,8 @@ Require-Bundle: org.junit,
  org.eclipse.ui.views.log,
  org.eclipse.debug.core,
  org.eclipse.pde.genericeditor.extension,
- org.eclipse.equinox.simpleconfigurator.manipulator;bundle-version="2.1.300",
- org.assertj;bundle-version="3.14.0"
+ org.eclipse.equinox.simpleconfigurator.manipulator;bundle-version="2.1.300"
+Import-Package: org.assertj.core.api;version="3.14.0"
 Eclipse-LazyStart: true
 Bundle-RequiredExecutionEnvironment: JavaSE-11
 Eclipse-BundleShape: dir