Move CalciteMgr::get impl into cpp file

Prevent python code from seeing static instance variable.

Author: alexbaden

omniscidb/Calcite/CalciteJNI.cpp

@@ -572,6 +572,14 @@ CalciteMgr::~CalciteMgr() {
   worker_.join();
 }
 
+CalciteMgr* CalciteMgr::get(const std::string& udf_filename, size_t calcite_max_mem_mb) {
+  std::call_once(instance_init_flag_, [=] {
+    instance_ =
+        std::unique_ptr<CalciteMgr>(new CalciteMgr(udf_filename, calcite_max_mem_mb));
+  });
+  return instance_.get();
+}
+
 std::string CalciteMgr::process(
     const std::string& db_name,
     const std::string& sql_string,

omniscidb/Calcite/CalciteJNI.h

@@ -43,13 +43,7 @@ class CalciteMgr {
   ~CalciteMgr();
 
   static CalciteMgr* get(const std::string& udf_filename = "",
-                         size_t calcite_max_mem_mb = 1024) {
-    std::call_once(instance_init_flag_, [=] {
-      instance_ =
-          std::unique_ptr<CalciteMgr>(new CalciteMgr(udf_filename, calcite_max_mem_mb));
-    });
-    return instance_.get();
-  }
+                         size_t calcite_max_mem_mb = 1024);
 
   std::string process(const std::string& db_name,
                       const std::string& sql_string,