[Macros] Don't import string-processing and backtracing

Other macro libraries e.g. ObservationMacros don't import them.

Author: rintaro

Sources/TestingMacros/CMakeLists.txt

@@ -104,6 +104,10 @@ target_sources(TestingMacros PRIVATE
   TestDeclarationMacro.swift
   TestingMacrosMain.swift)
 
+target_compile_options(TestingMacros PRIVATE
+  "SHELL:-Xfrontend -disable-implicit-string-processing-module-import"
+  "SHELL:-Xfrontend -disable-implicit-backtracing-module-import")
+
 target_link_libraries(TestingMacros PRIVATE
   SwiftSyntax::SwiftSyntax
   SwiftSyntax::SwiftSyntaxMacroExpansion