Avoid too many dictionary resizing to improve performance

[MoSelem]

No description provided.

[StefH]

@MoSelem
Did you use any memory analyzer to find this issue?

[MoSelem]

Yes, by analyzing AzureProfiler stack traces for a high "System.Int32[]" allocations, I noticed dictionary resizing happens multiple times through

System.Linq.Dynamic.Core.DynamicExpressionParser!ParseLambda
System.Linq.Dynamic.Core.Parser.ExpressionParser!.ctor
System.Linq.Dynamic.Core.Parser.KeywordsHelper!.ctor
mscorlib.ni.dll!System.Collections.Generic.Dictionary`2[System.__Canon,System.__Canon].Insert(System.__Canon, System.__Canon, Boolean)$##6003A62
mscorlib.ni.dll!System.Collections.Generic.Dictionary`2[System.__Canon,System.__Canon].Resize(Int32, Boolean)$##6003A65
clr.dll!`dynamic atexit destructor for 'AppDataPathHolder''
clr.dll!SVR::gc_heap::fire_etw_allocation_event
clr.dll!CoTemplate_qqhxpzqp
ntdll.dll!EtwEventWrite
ntdll.dll!EtwpEventWriteFull
ntdll.dll!ZwTraceEvent
System.Int32[]

[StefH]

because of PR #755, this PR is not valid anymore