impl(bigtable): add string literal constructor to Bytes (#15750)

Author: scotthart

google/cloud/bigtable/bytes.h

@@ -44,6 +44,9 @@ class Bytes {
   /// An empty sequence.
   Bytes() = default;
 
+  /// Stops copying at the null-terminator character from input bytes.
+  explicit Bytes(char const* bytes) : bytes_(bytes) {}
+
   /// @name Construction from a sequence of octets.
   ///@{
   template <typename InputIt>

google/cloud/bigtable/bytes_test.cc

@@ -105,8 +105,8 @@ TEST(Bytes, OutputStream) {
       {Bytes(std::string("a\377B")), R"(B"a\377B")"},
       {Bytes(std::string("!@#$%^&*()-.")), R"(B"!@#$%^&*()-.")"},
       {Bytes(std::string(3, '\0')), R"(B"\000\000\000")"},
-      {Bytes(""), R"(B"\000")"},
-      {Bytes("foo"), R"(B"foo\000")"},
+      {Bytes(""), R"(B"")"},
+      {Bytes("foo"), R"(B"foo")"},
   };
 
   for (auto const& tc : test_cases) {