[bolt] Stop setting config.llvm_plugin_ext in lit.site.cfg.py.in

[thakis]

Summary

config.llvm_plugin_ext is used by lit to set the %pluginext
substitution. bolt's tests don't use %pluginext, so they don't
need to set config.llvm_plugin_ext.

[thakis]

rebase

[thakis]

Thanks!

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

 @LIT_SITE_CFG_IN_HEADER@
 
 import sys
 
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.bolt_obj_root = "@BOLT_BINARY_DIR@"
 config.bolt_enable_runtime = @BOLT_ENABLE_RUNTIME@
 config.llvm_tools_dir = lit_config.substitute("@LLVM_TOOLS_DIR@")
 config.llvm_libs_dir = lit_config.substitute("@LLVM_LIBS_DIR@")
 config.llvm_shlib_dir = lit_config.substitute("@SHLIBDIR@")
-config.llvm_plugin_ext = "@LLVM_PLUGIN_EXT@"
 config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@"
 config.host_triple = "@LLVM_HOST_TRIPLE@"
 config.target_triple = "@LLVM_TARGET_TRIPLE@"
 config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@"
 config.host_arch = "@HOST_ARCH@"
 config.python_executable = "@Python3_EXECUTABLE@"
 config.bolt_clang = "@BOLT_CLANG_EXE@"
 config.bolt_lld = "@BOLT_LLD_EXE@"
 config.targets_to_build = "@TARGETS_TO_BUILD@"
 config.gnu_ld = "@GNU_LD_EXECUTABLE@"
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
 
 # Let the main config do the real work.
 lit_config.load_config(config, "@BOLT_SOURCE_DIR@/test/lit.cfg.py")