[test] Delete some xfailed lldb-mi tests

This is a first pass at removing some lldb-mi tests which have been
xfailed and unmaintained for a while. We have open PRs for most of these
tests already. I've opened up the following additional PRs:

  llvm.org/PR36739 - lldb-mi driver exits properly
  llvm.org/PR36740 - lldb-mi -gdb-set and -gdb-show
  llvm.org/PR36741 - lldb-mi -symbol-xxx

The motivation here is to address timeout and pexpect-related issues in
the test suite. This was discussed on lldb-dev in the thread: "increase
timeout for tests?".

After this change, the lldb-mi tests seem to be in better health (on
Darwin at least). I consistently get:

$ ./bin/llvm-dotest -p TestMi
===================
Test Result Summary
===================
Test Methods:        101
Reruns:                0
Success:              88
Expected Failure:      0
Failure:               0
Error:                 0
Exceptional Exit:      0
Unexpected Success:    0
Skip:                 13
Timeout:               0
Expected Timeout:      0

llvm-svn: 327552

Author: vedantk

lldb/packages/Python/lldbsuite/test/tools/lldb-mi/TestMiExit.py

@@ -15,29 +15,6 @@ class MiExecTestCase(lldbmi_testcase.MiTestCaseBase):
 
     mydir = TestBase.compute_mydir(__file__)
 
-    @skipIfRemote   # We do not currently support remote debugging via the MI.
-    @skipIfWindows  # llvm.org/pr24452: Get lldb-mi tests working on Windows
-    @skipIfFreeBSD  # llvm.org/pr22411: Failure presumably due to known thread races
-    @expectedFailureAll(
-        oslist=["linux"],
-        bugnumber="llvm.org/pr25000: lldb-mi does not receive broadcasted notification from Core/Process about process stopped")
-    def test_lldbmi_exec_run(self):
-        """Test that 'lldb-mi --interpreter' can stop at entry."""
-
-        self.spawnLldbMi(args=None)
-
-        # Load executable
-        self.runCmd("-file-exec-and-symbols %s" % self.myexe)
-        self.expect("\^done")
-
-        # Test that program is stopped at entry
-        self.runCmd("-exec-run --start")
-        self.expect("\^running")
-        self.expect(
-            "\*stopped,reason=\"signal-received\",signal-name=\"SIGSTOP\",signal-meaning=\"Stop\",.*?thread-id=\"1\",stopped-threads=\"all\"")
-        # Test that lldb-mi is ready to execute next commands
-        self.expect(self.child_prompt, exactly=True)
-
     @skipIfRemote   # We do not currently support remote debugging via the MI.
     @skipIfWindows  # llvm.org/pr24452: Get lldb-mi tests working on Windows
     @skipIfFreeBSD  # llvm.org/pr22411: Failure presumably due to known thread races