patch 8.1.1984: more functions can be used as methods

Problem:    More functions can be used as methods.
Solution:   Make various functions usable as a method.
diff --git a/src/testdir/test_perl.vim b/src/testdir/test_perl.vim
index 8f23f2c..b4df0ba 100644
--- a/src/testdir/test_perl.vim
+++ b/src/testdir/test_perl.vim
@@ -30,7 +30,7 @@
 
 funct Test_VIM_Blob()
   call assert_equal('0z',         perleval('VIM::Blob("")'))
-  call assert_equal('0z31326162', perleval('VIM::Blob("12ab")'))
+  call assert_equal('0z31326162', 'VIM::Blob("12ab")'->perleval())
   call assert_equal('0z00010203', perleval('VIM::Blob("\x00\x01\x02\x03")'))
   call assert_equal('0z8081FEFF', perleval('VIM::Blob("\x80\x81\xfe\xff")'))
 endfunc