trace_processor: move stringpool to new containers folder

This allows us to remove the ugly "common" target which has existed for
a long time.

Context: go/perfetto-tp-refactor
Bug: 135177627
Change-Id: I6dd03c22f0b42f818a9a53ad9bfa1e7f382a05f4
diff --git a/src/trace_processor/trace_storage.h b/src/trace_processor/trace_storage.h
index 56c92a0..a006864 100644
--- a/src/trace_processor/trace_storage.h
+++ b/src/trace_processor/trace_storage.h
@@ -32,10 +32,10 @@
 #include "perfetto/ext/base/string_view.h"
 #include "perfetto/ext/base/utils.h"
 #include "perfetto/trace_processor/basic_types.h"
+#include "src/trace_processor/containers/string_pool.h"
 #include "src/trace_processor/ftrace_utils.h"
 #include "src/trace_processor/metadata.h"
 #include "src/trace_processor/stats.h"
-#include "src/trace_processor/string_pool.h"
 #include "src/trace_processor/tables/counter_tables.h"
 #include "src/trace_processor/tables/profiler_tables.h"
 #include "src/trace_processor/tables/slice_tables.h"