Optimize location conversion

[sungam3r]

I spent on writing and debugging this algorithm a bunch of time. Although this code is performed only when making exception messages, I wanted to get rid of the regular expression. No memory allocations at all now. If you check code before changes on a rather big query, then you will make sure that the work with a regular expression here generates an abnormal amount of memory allocations.

fixes #102

[sungam3r]

@Shane32 I added these notes to make ROM usage by other projects more understandable.

[sungam3r]

Example:

        string d = "KitchenSink".ReadGraphQLFile();

        for (int i = 0; i < 100; ++i)
        {
            var m1 = GC.GetAllocatedBytesForCurrentThread();
            var loc = new Location(d, 3000);
            var m2 = GC.GetAllocatedBytesForCurrentThread();
            var delta = m2 - m1;
        }

var matches = _lineRegex.Matches((string)source); returns collection with 152 items. Each loop iteration increases memory by 35968 bytes! After changes delta=0 on each loop iteration.

[sungam3r]

I'll add tests for 100% coverage later, 3:30AM here.

[sungam3r]

The desire to get full coverage again made it possible to find a bug.

[codecov-commenter]

Codecov Report

Merging #202 (82772f2) into master (16376af) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #202   +/-   ##
=======================================
  Coverage   98.75%   98.76%           
=======================================
  Files          85       85           
  Lines        4411     4438   +27     
  Branches      434      437    +3     
=======================================
+ Hits         4356     4383   +27     
  Misses         33       33           
  Partials       22       22           

Impacted Files	Coverage Δ
src/GraphQLParser/ROM.cs	100.00% <ø> (ø)
src/GraphQLParser/Location.cs	100.00% <100.00%> (ø)

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