[lldb] Make TestJitBreakPoint.py use LLVM_TOOLS_DIR (llvm#171656)

This seems the standard way to get the path to such tools within LLVM.
Calling findBuiltClang() has some annoying behavior like falling back to
CC when it cannot find anything else, which might point to anything or
not even be set.

We noticed this with our internal build system as the lli binary is not
in the same path as the clang binary.

Author: boomanaiden154

lldb/test/API/functionalities/breakpoint/jit_loader_rtdyld_elf/TestJitBreakPoint.py

@@ -5,6 +5,7 @@
 import lldb
 from lldbsuite.test.decorators import *
 from lldbsuite.test.lldbtest import *
+from lldbsuite.test import configuration
 
 
 class TestJitBreakpoint(TestBase):
@@ -20,9 +21,11 @@ def test_jit_breakpoints(self):
     def do_test(self, jit_flag: str):
         self.runCmd("settings set plugin.jit-loader.gdb.enable on")
 
-        clang_path = self.findBuiltClang()
-        self.assertTrue(clang_path, "built clang could not be found")
-        lli_path = os.path.join(os.path.dirname(clang_path), "lli")
+        self.assertIsNotNone(
+            configuration.llvm_tools_dir,
+            "llvm_tools_dir must be set to find lli",
+        )
+        lli_path = os.path.join(os.path.join(configuration.llvm_tools_dir, "lli"))
         self.assertTrue(lldbutil.is_exe(lli_path), f"'{lli_path}' is not an executable")
         self.runCmd(f"target create {lli_path}", CURRENT_EXECUTABLE_SET)