Fix hanging with many curly-bracket pairs, bug663.

	* verilog-mode.el (verilog-at-constraint-p)
	(verilog-beg-of-statement-1): Fix hanging with many curly-bracket
	pairs, bug663.
Add tests for forever, foreach, and do..while indentation
Add additional loop constructs to verilog-no-indent-begin-re

When verilog-indent-begin-after-if is nil, certain keywords should not
trigger indentation of a trailing 'begin' statement.  This list now
includes the looping keywords 'do', 'foreach', and 'forever'.