Add another testing proving that inline partials can occur before the block definition.

js/test_cases/block_before/base.dust

@@ -0,0 +1 @@
+The block content is from {+inject/}

js/test_cases/block_before/input1.json

@@ -0,0 +1,4 @@
+{"people": [
+  {"name": "Alice", "item": "cat"},
+  {"name": "Bob"}
+]}

js/test_cases/block_before/main.dust

@@ -0,0 +1,2 @@
+{<inject}Before Partial{/inject}
+{>"base"/}