patch 8.2.0155: warnings from MinGW compiler; tests fail without +float

Problem:    Warnings from MinGW compiler. (John Marriott) Json test fails when
            building without +float feature.
Solution:   Init variables. Fix Json parsing. Skip a few tests that require
            the +float feature.

src/vim9compile.c

@@ -1217,8 +1217,13 @@ parse_type(char_u **arg, garray_T *type_list)
 	case 'f':
 	    if (len == 5 && STRNCMP(*arg, "float", len) == 0)
 	    {
+#ifdef FEAT_FLOAT
 		*arg += len;
 		return &t_float;
+#else
+		emsg(_("E1055: This Vim is not compiled with float support"));
+		return &t_any;
+#endif
 	    }
 	    if (len == 4 && STRNCMP(*arg, "func", len) == 0)
 	    {