Improve parse_static_options speed

Comparing each element of the static options with each incoming element
is very inefficient. Since dictionaries are ordered this can be
simplified to a simple key value insert.

Prior to this change:
```
parse_static_options (/Users/mvandenb/src/galaxy/lib/galaxy/tool_util/parser/xml.py:1207)
function called 7183 times

         313317 function calls in 11.318 seconds

   Ordered by: cumulative time, internal time, call count

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
     7183   11.281    0.002   11.318    0.002 xml.py:1207(parse_static_options)
    99675    0.029    0.000    0.033    0.000 __init__.py:1004(string_as_bool)
    99675    0.004    0.000    0.004    0.000 {method 'lower' of 'str' objects}
    99601    0.004    0.000    0.004    0.000 {method 'append' of 'list' objects}
     7183    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}
        0    0.000             0.000          profile:0(profiler)
```
after:
```
*** PROFILER RESULTS ***
parse_static_options (/Users/mvandenb/src/galaxy/lib/galaxy/tool_util/parser/xml.py:1207)
function called 7183 times

         220899 function calls in 0.260 seconds

   Ordered by: cumulative time, internal time, call count

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
     7183    0.230    0.000    0.259    0.000 xml.py:1207(parse_static_options)
    99675    0.026    0.000    0.029    0.000 __init__.py:1004(string_as_bool)
    99675    0.004    0.000    0.004    0.000 {method 'lower' of 'str' objects}
     7183    0.000    0.000    0.000    0.000 {method 'values' of 'dict' objects}
     7183    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}
        0    0.000             0.000          profile:0(profiler)
```

This is most due to openms_idfilter, which has 2928 static options.

lib/galaxy/tool_util/parser/xml.py

@@ -1214,21 +1214,16 @@ def parse_static_options(self):
         >>> xis.parse_static_options()
         [('a', 'a', True), ('b', 'b', False)]
         """
-        static_options = list()
+
+        deduplicated_static_options = {}
+
         elem = self.input_elem
         for option in elem.findall("option"):
             value = option.get("value")
             text = option.text or value
             selected = string_as_bool(option.get("selected", False))
-            present = False
-            for i, o in enumerate(static_options):
-                if o[1] == value:
-                    present = True
-                    static_options[i] = (text, value, selected)
-                    break
-            if not present:
-                static_options.append((text, value, selected))
-        return static_options
+            deduplicated_static_options[value] = (text, value, selected)
+        return list(deduplicated_static_options.values())
 
     def parse_optional(self, default=None):
         """Return boolean indicating whether parameter is optional."""