Add expected type parameter to evaluate_expression

Add expected type parameter to evaluate_expression

While working on the expression rewrite, I found a few spots that
called the internal functions of the expression evaluator, just to
pass in an expected type.  This patch adds a parameter to
evaluate_expression so that these functions can avoid this dependency.

Regression tested on x86-64 Fedora 28.

gdb/ChangeLog
2020-12-15  Tom Tromey  <tom@tromey.com>

	* stap-probe.c (stap_probe::evaluate_argument): Use
	evaluate_expression.
	* dtrace-probe.c (dtrace_probe::evaluate_argument): Use
	evaluate_expression.
	* value.h (evaluate_expression): Add expect_type parameter.
	* objc-lang.c (print_object_command): Call evaluate_expression.
	* eval.c (evaluate_expression): Add expect_type parameter.