adb: add helper to consume a prefix on a string_view.

It's error-prone to manually writing code of the following form:

  if (foo.starts_with("some_prefix:")) {
    foo.remove_prefix(strlen("some_prefix:"));
  }

Add a helper to do that for us.

Test: mma
Change-Id: I5df391deba8b6c036fcbf17a1f1c79af8d9abd2b

adb/adb_utils.h

@@ -141,3 +141,11 @@ inline bool ParseUint(T* result, std::string_view str, std::string_view* remaini
 
     return true;
 }
+
+inline bool ConsumePrefix(std::string_view* str, std::string_view prefix) {
+  if (str->starts_with(prefix)) {
+    str->remove_prefix(prefix.size());
+    return true;
+  }
+  return false;
+}