Remove some references to/compatibility issues for Ruby 3.2

Author: herwinw

command_line/dash_r_spec.rb

@@ -16,10 +16,7 @@
     out = ruby_exe(fixture(__FILE__, "bad_syntax.rb"), options: "-r #{@test_file}", args: "2>&1", exit_status: 1)
     $?.should_not.success?
     out.should include("REQUIRED")
-
-    # it's tempting not to rely on error message and rely only on exception class name,
-    # but CRuby before 3.2 doesn't print class name for syntax error
-    out.should include_any_of("syntax error", "SyntaxError")
+    out.should include("SyntaxError")
   end
 
   it "does not require the file if the main script file does not exist" do

core/unboundmethod/equal_value_spec.rb

@@ -110,9 +110,6 @@ class << self
     c.method(:n).should == Class.instance_method(:new).bind(c)
   end
 
-  # On CRuby < 3.2, the 2 specs below pass due to method/instance_method skipping zsuper methods.
-  # We are interested in the general pattern working, i.e. the combination of method/instance_method
-  # and #== exposes the wanted behavior.
   it "considers methods through visibility change equal" do
     c = Class.new do
       class << self

shared/kernel/at_exit.rb

@@ -60,10 +60,7 @@
     result = ruby_exe('{', options: "-r#{script}", args: "2>&1", exit_status: 1)
     $?.should_not.success?
     result.should.include?("handler ran\n")
-
-    # it's tempting not to rely on error message and rely only on exception class name,
-    # but CRuby before 3.2 doesn't print class name for syntax error
-    result.should include_any_of("syntax error", "SyntaxError")
+    result.should include("SyntaxError")
   end
 
   it "calls the nested handler right after the outer one if a handler is nested into another handler" do