some lldb tests ignore LLDB_TEST_TRIPLE/LLDB_TEST_COMPILER

Building LLVM with a default triple which isn't the host triple, the following tests fail because they expect the just-built clang can build programs without specifying any arguments:

```
lldb-shell :: Breakpoint/breakpoint-command.test
lldb-shell :: Breakpoint/dummy-target.test
lldb-shell :: Driver/TestConvenienceVariables.test
lldb-shell :: Expr/TestAnonNamespaceParamFunc.cpp
lldb-shell :: Expr/TestExprWithSideEffect.cpp
lldb-shell :: Expr/TestExprWithSideEffectOnConvenienceVar.cpp
lldb-shell :: Settings/TestCxxFrameFormatObjC.test
lldb-shell :: Settings/TestFrameFormatName.test
lldb-shell :: SymbolFile/NativePDB/lookup-by-types.cpp
lldb-shell :: SymbolFile/OnDemand/source-breakpoint.test
lldb-shell :: SymbolFile/OnDemand/symbolic-breakpoint.test
```

Most lldb tests respect LLDB_TEST_TRIPLE/LLDB_TEST_COMPILER, but these don't.

----------------

There are also a few other tests which apparently respect LLDB_TEST_COMPILER, but not LLDB_TEST_TRIPLE:

```
lldb-api :: functionalities/scripted_process/TestScriptedProcess.py
lldb-api :: lang/c/calling-conventions/TestCCallingConventions.py
lldb-api :: tools/lldb-dap/stackTraceDisassemblyDisplay/TestDAP_stackTraceDisassemblyDisplay.py
```

Start by running the listed lldb-shell and lldb-api tests with a non-host default triple, then inspect the named Breakpoint, Expr, Settings, SymbolFile, and Python test files. Compare how nearby LLDB tests consume LLDB_TEST_TRIPLE and LLDB_TEST_COMPILER. Done means every listed test respects the relevant settings and passes under the non-host configuration.

Written by the indexing model from the issue text.