Revert "Temporarily disable tests on Linux (5.6 branch only)"

This reverts commit 200098b.

Author: adrian-prantl

lldb/test/API/lang/swift/implementation_only_imports/library_indirect/TestLibraryIndirect.py

@@ -78,7 +78,6 @@ def cleanup():
         self.expect("e container.wrapped.value", substrs=["(SomeLibraryCore.TwoInts)", "(first = 2, second = 3)"])
 
     @swiftTest
-    @skipIfLinux # The "e container" command crashes in a non-reproducible way on the Linux bots.
     def test_implementation_only_import_library_no_library_module(self):
         """Test `@_implementationOnly import` behind some indirection in a library used by the main executable, after removing the implementation-only library's swiftmodule
 

lldb/test/API/lang/swift/implementation_only_imports/library_resilient/TestLibraryResilient.py

@@ -65,7 +65,6 @@ def cleanup():
 
     @swiftTest
     @expectedFailureAll(oslist=["windows"]) # Requires Remote Mirrors support
-    @skipIfLinux # The "e container" command crashes in a non-reproducible way on the Linux bots.
     def test_implementation_only_import_library_no_library_module(self):
         """Test `@_implementationOnly import` in a resilient library used by the main executable, after removing the implementation-only library's swiftmodule