Fix skipcrossgen option (dotnet/coreclr#12650)

* Fix skipcrossgen option

* Use return instead of exit

Commit migrated from https://github.com/dotnet/coreclr/commit/8b4d63bea132d4cb73933ca9e2411f55bca1f539

diff --git a/src/coreclr/build.sh b/src/coreclr/build.sh
index 6ec1ceb..55483ce 100755 (executable)
--- a/src/coreclr/build.sh
+++ b/src/coreclr/build.sh
@@ -406,6 +406,7 @@ build_CoreLib_ni()
 {
     if [ $__SkipCrossgen == 1 ]; then
         echo "Skipping generating native image"
+        return
     fi
 
     if [ $__SkipCoreCLR == 0 -a -e $__BinDir/crossgen ]; then