[test] better names for test suites

Author: glessard

test/stdlib/Span/ArrayStorage.swift

@@ -16,7 +16,7 @@
 
 import StdlibUnittest
 
-var suite = TestSuite("ArrayStorageProperty")
+var suite = TestSuite("Array-Backed Span Properties")
 defer { runAllTests() }
 
 suite.test("Array.span property")

test/stdlib/Span/InlineStorage.swift

@@ -17,7 +17,7 @@
 
 import StdlibUnittest
 
-var suite = TestSuite("InlineTypesStorageProperty")
+var suite = TestSuite("Span properties backed by inline storage")
 defer { runAllTests() }
 
 suite.test("CollectionOfOne.span property")