tests/basics: Move str/bytes tests that give SyntaxWarning to sep file.

In CPython 3.12 these invalid str/bytes/fstring escapes will issue a
SyntaxWarning, and so differ to MicroPython.
Signed-off-by: Damien George <damien@micropython.org>

tests/basics/bytes.py

@@ -2,7 +2,6 @@
 print(b'123')
 print(br'123')
 print(rb'123')
-print(b'\u1234')
 
 # construction
 print(bytes())

tests/basics/bytes_escape_unicode.py

+# Coverage test for unicode escape in a bytes literal.
+# CPython issues a SyntaxWarning for this.
+print(b"\u1234")

tests/basics/bytes_escape_unicode.py.exp

+b'\\u1234'

tests/basics/string1.py

@@ -5,7 +5,6 @@ print('abc')
 print(r'abc')
 print(u'abc')
 print(repr('\a\b\t\n\v\f\r'))
-print('\z') # unrecognised escape char
 
 # construction
 print(str())

tests/basics/string_escape_invalid.py

+# Test invalid escape characters.
+# CPython issues a SyntaxWarning for this.
+
+print("\z")

tests/basics/string_escape_invalid.py.exp

+\z

tests/basics/string_fstring.py

@@ -29,21 +29,6 @@ print(f"a{[0,15,2][0:2][-1]:04x}")
 # Nested '{' and '}' characters.
 print(f"a{ {0,1,2}}")
 
-# PEP-0498 specifies that '\\' and '#' must be disallowed explicitly, whereas
-# MicroPython relies on the syntax error as a result of the substitution.
-
-print(f"\\")
-print(f'#')
-try:
-    eval("f'{\}'")
-except SyntaxError:
-    print('SyntaxError')
-try:
-    eval("f'{#}'")
-except SyntaxError:
-    print('SyntaxError')
-
-
 # PEP-0498 specifies that handling of double braces '{{' or '}}' should
 # behave like str.format.
 print(f'{{}}')

tests/basics/string_fstring_invalid.py

+# PEP-0498 specifies that '\\' and '#' must be disallowed explicitly, whereas
+# MicroPython relies on the syntax error as a result of the substitution.
+
+print(f"\\")
+print(f"#")
+try:
+    eval("f'{\}'")
+except SyntaxError:
+    print("SyntaxError")
+try:
+    eval("f'{#}'")
+except SyntaxError:
+    print("SyntaxError")

tests/basics/string_fstring_invalid.py.exp

+\
+#
+SyntaxError
+SyntaxError