Removed all "perf" tests, as they made no sense.

Perftests for AttributeStorage was "perf" testing 3 implementations,
2 of them were totally unused (map one?) and irrelevant. The whole test
made no sense, as they were implemented at the time of Nx 2.0 when
we wanted to choose the tech that will supersede the XStream backed
one.

Same for LocalStorage, as the two test had no substantial difference,
and they were meant to catch attribute handling related problems, such
as slowdowns. Back then, there were no load tests, or any other kind
of real perf tests, so I removed them too.

Both set of tests were a muddy mixture of mocks, trickeries and such,
making the PITA to fix them, while again, their value is questionable.

nexus/nexus-core/src/test/java/org/sonatype/guice/nexus/scanners/NexusTypeVisitorTest.java

@@ -199,7 +199,7 @@ public void testNexusTypeScanning()
 
         // nexus-core: squash of modules causes to have more than 11
         // TODO: review this to somehow isolate this
-        Assert.assertEquals( 20, components.size() );
+        Assert.assertEquals( 19, components.size() );
 
         // non-extension so no automatic hinting...
         Assert.assertEquals( BeanA.class,