Consume SVG rasterizer via capability in SWT tests bundle

Currently, requiring an SVG rasterizer needs manual placement of an
according fragment on the classpath. With this change, requiring SVG
support can be defined explicitly via a required capability that is
provided by the according SWT fragment.

Contributes to
#1944

Author: HeikoKlare

bundles/org.eclipse.swt.svg/META-INF/MANIFEST.MF

@@ -11,3 +11,4 @@ Import-Package: com.github.weisj.jsvg;version="[1.7.0,2.0.0)",
  com.github.weisj.jsvg.geometry.size;version="[1.7.0,2.0.0)",
  com.github.weisj.jsvg.parser;version="[1.7.0,2.0.0)"
 Export-Package: org.eclipse.swt.svg
+Provide-Capability: osgi.extender;osgi.extender="org.eclipse.swt.svgrasterizer"

tests/org.eclipse.swt.tests/META-INF/MANIFEST.MF

@@ -20,3 +20,4 @@ Require-Bundle: org.junit;bundle-version="4.13.2",
 Eclipse-BundleShape: dir
 Bundle-RequiredExecutionEnvironment: JavaSE-17
 Automatic-Module-Name: org.eclipse.swt.tests
+Require-Capability: osgi.extender;filter:="(osgi.extender=org.eclipse.swt.svgrasterizer)"