* infrun.c (wait_for_inferior): Disable questionable code near

	* infrun.c (wait_for_inferior):  Disable questionable code near
	the step range test.  Replace call detection test with much
	simpler (and more efficient) test that doesn't require prologue
	examination (as often).
	* symtab.c symtab.h (in_prologue):  New function that indicates
	whether or not we are in a function prologue.  This uses the
	symbol table, and then falls back to prologue examination if that
	fails.  It's much more efficient for remote debugging because it
	avoids examining memory, which is very slow.  This is used in
	wait_for_inferior to determine if we've made a function call that
	needs to be skipped over (for next/nexti).
	* mips-tdep.c (after_prologue):  New function, returns the PC
	after the prologue.  Uses PDRs and the symbol table.
	(mips_find_saved_regs):  Use in_prologue() to avoid costly
	prologue examination if possible.
	(mips_skip_prologue):  Use after_prologue() if possible to avoid
	costly prologue examination.