[lldb] config.test_exec_root is set by lit.cfg.py

Don't configure `test_exec_root` in lit.site.cfg.py. It always gets
overwritten by lit.cfg.py based on `lldb_obj_root`.

Author: JDevlieghere

lldb/test/API/lit.site.cfg.py.in

@@ -1,6 +1,5 @@
 @LIT_SITE_CFG_IN_HEADER@
 
-config.test_exec_root = "@LLDB_BINARY_DIR@"
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"

lldb/test/Unit/lit.site.cfg.py.in

@@ -1,6 +1,5 @@
 @LIT_SITE_CFG_IN_HEADER@
 
-config.test_exec_root = "@LLDB_BINARY_DIR@"
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"

lldb/test/lit.site.cfg.py.in

@@ -1,6 +1,5 @@
 @LIT_SITE_CFG_IN_HEADER@
 
-config.test_exec_root = "@LLDB_BINARY_DIR@"
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"