fix dotnet host search (#4124)

* fix dotnet host search
- added performMultiLevelLookup

* Added runtime to unitTests step

* Changed patch version in semver of runtime

* remove sdk and runtime from unitTests script

* Fixed problem with .NET Core 3.1 installation

* Added UseDotNet task in functionalTests

Co-authored-by: Roman Shchukin <roman.shchukin@akvelon.com>

.azure-pipelines/build-job.yml

@@ -124,6 +124,15 @@ jobs:
 
   # Run l0 tests
   - ${{ if parameters.unitTests }}:
+    - ${{ if and(eq(parameters.os, 'win'), eq(parameters.arch, 'x86')) }}:
+      - task: UseDotNet@2
+        displayName: Install .NET Core 3.1 SDK
+        inputs:
+          version: '3.1.x'
+          packageType: 'runtime'
+          installationPath: 'C:\Program Files (x86)\dotnet'
+        env:
+          PROCESSOR_ARCHITECTURE: x86
     - script: ${{ variables.devCommand }} testl0 Debug ${{ parameters.os }}-${{ parameters.arch }}
       workingDirectory: src
       displayName: Unit tests
@@ -139,9 +148,10 @@ jobs:
       - task: UseDotNet@2
         displayName: Install .NET Core 3.1 SDK
         inputs:
-          version: '3.1.22'
+          version: '3.1.x'
           packageType: runtime
           performMultiLevelLookup: true
+          installationPath: 'C:\Program Files (x86)\dotnet'
     - script: ${{ variables.devCommand }} testl1 Debug ${{ parameters.os }}-${{ parameters.arch }}
       workingDirectory: src
       displayName: Functional tests