Don't unfreeze too early

This change removes an unnecessary (and incorrect) unfreezing during the
install flow. Removal ensures that all state from the previous version
of the updating app has been cleaned up before unfreeze and launch of
the app.

Bug: 136731650
Test: atest AtomicInstallTests AppSecurityTests
Change-Id: I477a6c352268caf5031d85bf8bd8d322e7472f33

services/core/java/com/android/server/pm/PackageManagerService.java

@@ -17035,11 +17035,6 @@ public class PackageManagerService extends IPackageManager.Stub
                     commitPackagesLocked(commitRequest);
                     success = true;
                 } finally {
-                    for (PrepareResult result : prepareResults.values()) {
-                        if (result.freezer != null) {
-                            result.freezer.close();
-                        }
-                    }
                     Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
                 }
             }