Fix macOS build for Flutter plugins (#13814)

packages/flutter_tools/templates/cocoapods/Podfile-objc

@@ -7,7 +7,9 @@ def parse_KV_file(file,seperator='=')
     return [];
   end
   pods_ary = []
+  skip_line_start_symbols = ["#", "/"]
   File.foreach(file_abs_path) { |line|
+      next if skip_line_start_symbols.any? { |symbol| line =~ /^\s*#{symbol}/ }
       plugin = line.split(pattern=seperator)
       if plugin.length == 2
         podname = plugin[0].strip()
@@ -22,7 +24,6 @@ def parse_KV_file(file,seperator='=')
 end
 
 target 'Runner' do
-  use_frameworks!
   # Flutter Pods
   generated_xcode_build_settings = parse_KV_file("./Flutter/Generated.xcconfig")
   if generated_xcode_build_settings.empty?

packages/flutter_tools/templates/cocoapods/Podfile-swift

@@ -7,7 +7,9 @@ def parse_KV_file(file,seperator='=')
     return [];
   end
   pods_ary = []
+  skip_line_start_symbols = ["#", "/"]
   File.foreach(file_abs_path) { |line|
+      next if skip_line_start_symbols.any? { |symbol| line =~ /^\s*#{symbol}/ }
       plugin = line.split(pattern=seperator)
       if plugin.length == 2
         podname = plugin[0].strip()