disable merge services for test compilation

Saw strange behavior when I tried excluding the events dependency and running tests

Author: SentryMan

inject-generator/src/main/java/io/avaje/inject/generator/ProcessingContext.java

@@ -35,7 +35,10 @@ static final class Ctx {
     private final Set<String> spiServices = new TreeSet<>();
     private final Set<String> externalSpi = new TreeSet<>();
     private boolean strictWiring;
-    private final boolean mergeServices = APContext.getOption("mergeServices").map(Boolean::valueOf).orElse(true);
+    private final boolean mergeServices =
+        APContext.getOption("mergeServices")
+            .map(Boolean::valueOf)
+            .orElse(!APContext.isTestCompilation());
 
     void registerProvidedTypes(Set<String> moduleFileProvided) {
       ExternalProvider.registerModuleProvidedTypes(providedTypes);