[gdb/testsuite] Add missing require {!is_remote host}

I ran test-case gdb.python/py-color-pagination.exp with make-check-all.sh and
noticed failures when using remote host.

So I grepped to find all test-cases using with_ansi_styling_terminal and ran
them with host/target board local-remote-host-native.

Fix the failing test-cases using require {!is_remote host}.

Tested on x86_64-linux.

gdb/testsuite/gdb.guile/scm-color.exp

@@ -19,6 +19,7 @@
 load_lib gdb-guile.exp
 
 require allow_guile_tests
+require {!is_remote host}
 
 # Start GDB with styling support.
 with_ansi_styling_terminal {

gdb/testsuite/gdb.python/py-color-pagination.exp

@@ -19,6 +19,7 @@
 load_lib gdb-python.exp
 
 require allow_python_tests
+require {!is_remote host}
 
 standard_testfile
 

gdb/testsuite/gdb.python/py-color.exp

@@ -18,6 +18,7 @@
 load_lib gdb-python.exp
 
 require allow_python_tests
+require {!is_remote host}
 
 # Start with a fresh GDB, but enable color support.
 with_ansi_styling_terminal {

gdb/testsuite/gdb.python/py-format-string.exp

@@ -1202,7 +1202,9 @@ with_test_prefix "format_string" {
 	set current_lang "c"
 	prepare_gdb "${binfile}"
 	test_all_common
-	test_styling
+	if { ![is_remote host] } {
+	    test_styling
+	}
       }
     }
   }

gdb/testsuite/gdb.python/py-startup-opt.exp

@@ -17,6 +17,7 @@
 # initialized.
 
 require allow_python_tests
+require {!is_remote host}
 
 # Return a list containing two directory paths for newly created home
 # directories.

gdb/testsuite/gdb.python/py-styled-execute.exp

@@ -17,6 +17,7 @@
 # on the value of the third argument passed to gdb.execute.
 
 require allow_python_tests
+require {!is_remote host}
 
 load_lib gdb-python.exp