Remove unused __RemoveThisBitTo__GENERATE_BASELINES compilation symbol

This doesn't appear to be used anywhere.

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Microsoft.AspNetCore.Razor.LanguageServer.Test.csproj

@@ -5,7 +5,6 @@
 
     <!-- To generate baselines, run tests with /p:GenerateBaselines=true -->
     <DefineConstants Condition="'$(GenerateBaselines)'=='true'">$(DefineConstants);GENERATE_BASELINES</DefineConstants>
-    <DefineConstants>$(DefineConstants);__RemoveThisBitTo__GENERATE_BASELINES</DefineConstants>
   </PropertyGroup>
 
   <ItemGroup>

src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/Microsoft.AspNetCore.Razor.Test.Common.Tooling.csproj

@@ -8,7 +8,6 @@
 
     <!-- To generate baselines, run tests with /p:GenerateBaselines=true -->
     <DefineConstants Condition="'$(GenerateBaselines)'=='true'">$(DefineConstants);GENERATE_BASELINES</DefineConstants>
-    <DefineConstants>$(DefineConstants);__RemoveThisBitTo__GENERATE_BASELINES</DefineConstants>
 
     <!-- We only import JSON serialization on non-NetFx.
          For NetFx, we rely on the JSON serialization compiled into Microsoft.VisualStudio.LanguageService.Razor for Live Share. -->

src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Microsoft.AspNetCore.Razor.Test.Common.csproj

@@ -3,7 +3,6 @@
   <PropertyGroup>
     <!-- To generate baselines, run tests with /p:GenerateBaselines=true -->
     <DefineConstants Condition="'$(GenerateBaselines)'=='true'">$(DefineConstants);GENERATE_BASELINES</DefineConstants>
-    <DefineConstants>$(DefineConstants);__RemoveThisBitTo__GENERATE_BASELINES</DefineConstants>
     <TargetFrameworks>$(DefaultNetCoreTargetFrameworks);$(DefaultNetFxTargetFramework)</TargetFrameworks>
   </PropertyGroup>