build: statically link ArgumentParserToolInfo always (#424)

Now that windows supports static linking as well (to a certain degree),
alter the build of swift-argument-parser in CMake to use static linking
for ArgumentParserToolInfo always irrespective of whether ArgumentParser
is being built as a static library or a dynamic library.  On Windows, in
release mode, this saves ~32KiB.  Additionally, because no tool directly
links against this library, no binaries are further expanded by static
linking, and we have one less file to distribute.

Sources/ArgumentParserToolInfo/CMakeLists.txt

@@ -1,4 +1,4 @@
-add_library(ArgumentParserToolInfo
+add_library(ArgumentParserToolInfo STATIC
   ToolInfo.swift)
 # NOTE: workaround for CMake not setting up include flags yet
 set_target_properties(ArgumentParserToolInfo PROPERTIES
@@ -7,5 +7,4 @@ target_compile_options(ArgumentParserToolInfo PRIVATE
   $<$<BOOL:${BUILD_TESTING}>:-enable-testing>)
 
 
-_install_target(ArgumentParserToolInfo)
 set_property(GLOBAL APPEND PROPERTY ArgumentParser_EXPORTS ArgumentParserToolInfo)