try_compile: Add test for bad call error cases

Add a RunCMake.try_compile test to cover cases of bad invocation of the
try_compile command.
try_compile: Refactor argument processing

Process all arguments in a single loop using a simple state machine.
While at it, fix some error message typos.  Also allow LINK_LIBRARIES
with no actual libraries to disable use of the -DLINK_LIBRARIES=...
from the CMAKE_FLAGS.  This was already possible in the old logic if
LINK_LIBRARIES was immediately followed by another keyword argument
instead of the end of the argument list, so allow it in general.
Update the RunCMake.try_compile test cases accordingly.
Merge topic 'refactor-try_compile-argument-processing' into next

d06db7e try_compile: Refactor argument processing
b680824 try_compile: Add test for bad call error cases