[lldb] Remove license headers from all test source files

Summary:
Around a third of our test sources have LLVM license headers. This patch removes those headers from all test
sources and also fixes any tests that depended on the length of the license header.

The reasons for this are:

* A few tests verify line numbers and will start failing if the number of lines in the LLVM license header changes. Once I landed my patch for valid SourceLocations in debug info we will probably have even more tests that verify line numbers.
* No other LLVM project is putting license headers in its test files to my knowledge.
* They make the test sources much more verbose than they have to be. Several tests have longer license headers than the actual test source.

For the record, the following tests had their line numbers changed to pass with the removal of the license header:
    lldb-api :: functionalities/breakpoint/breakpoint_by_line_and_column/TestBreakpointByLineAndColumn.py
    lldb-shell :: Reproducer/TestGDBRemoteRepro.test
    lldb-shell :: Reproducer/TestMultipleTargets.test
    lldb-shell :: Reproducer/TestReuseDirectory.test
    lldb-shell :: ExecControl/StopHook/stop-hook-threads.test
    lldb-shell :: ExecControl/StopHook/stop-hook.test
    lldb-api :: lang/objc/exceptions/TestObjCExceptions.py

Reviewers: #lldb, espindola, JDevlieghere

Reviewed By: #lldb, JDevlieghere

Subscribers: emaste, aprantl, arphaman, JDevlieghere, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D74839